WO2017179268A1 - Aqueous polyimide dispersion, binder for electrodes, electrode, secondary battery and method for producing aqueous polyimide dispersion - Google Patents

Aqueous polyimide dispersion, binder for electrodes, electrode, secondary battery and method for producing aqueous polyimide dispersion Download PDF

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Publication number
WO2017179268A1
WO2017179268A1 PCT/JP2017/003346 JP2017003346W WO2017179268A1 WO 2017179268 A1 WO2017179268 A1 WO 2017179268A1 JP 2017003346 W JP2017003346 W JP 2017003346W WO 2017179268 A1 WO2017179268 A1 WO 2017179268A1
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Prior art keywords
polyimide
aqueous dispersion
acid
particularly limited
electrode
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PCT/JP2017/003346
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French (fr)
Japanese (ja)
Inventor
汰玖哉 吉岡
聡哉 渡邊
宮村　岳志
修一 伊藤
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第一工業製薬株式会社
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Priority claimed from JP2016081177A external-priority patent/JP6062090B1/en
Priority claimed from JP2016081178A external-priority patent/JP6062091B1/en
Application filed by 第一工業製薬株式会社 filed Critical 第一工業製薬株式会社
Publication of WO2017179268A1 publication Critical patent/WO2017179268A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a polyimide aqueous dispersion, an electrode binder, an electrode, a secondary battery, and a method for producing a polyimide aqueous dispersion.
  • Polyimide is used in a wide range of applications.
  • the use to the negative electrode for lithium ion secondary batteries is disclosed (patent document 1).
  • a thermosetting urethane imide composition obtained by using polyisocyanate and without solvent is disclosed (Patent Document 2).
  • JP 2002-37848 A Japanese Patent Laid-Open No. 2015-220221
  • Patent Document 1 In the method of Patent Document 1, it is necessary to use an explosion-proof structure for the equipment used, and improvement has been desired. In addition, a polyimide having a great effect of improving the mechanical strength has been demanded.
  • the inventors of the present invention paid attention to an aqueous dispersion of polyimide in order to solve the above-mentioned problems and studied.
  • an aqueous dispersion By using an aqueous dispersion, the environmental compatibility is high, it is not necessary to make the equipment used an explosion-proof structure, and the effect of improving the mechanical strength is great.
  • (A) an acid anhydride, (B) polyisocyanate, and (C) a polyimide aqueous dispersion obtained by reacting one or more active hydrogen groups and a compound having a hydrophilic group are used.
  • a polyimide aqueous dispersion obtained by reacting (A) an acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group.
  • the polyimide water dispersion as described in (1) whose acid value is 50 mgKOH / g or less.
  • the polyimide aqueous dispersion of the present invention is an aqueous dispersion, it has high environmental compatibility, and there is no need to make the equipment used an explosion-proof structure. Moreover, the improvement effect of mechanical strength is also great.
  • the polyimide aqueous dispersion of the present embodiment is obtained by reacting (A) acid anhydride, (B) polyisocyanate, and (C) one or more active hydrogen groups and a compound having a hydrophilic group.
  • the (A) acid anhydride of the present embodiment is a carboxylic acid anhydride and is not particularly limited as long as it is a compound obtained by dehydration condensation of two molecules of carboxylic acid.
  • the (A) acid anhydride of the present embodiment is a carboxylic acid anhydride and is not particularly limited as long as it is a compound obtained by dehydration condensation of two molecules of carboxylic acid.
  • 1,2,3,4-butanetetracarboxylic dianhydride pyromellitic anhydride (PMDA), 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo- 3-furanyl) naphtho [1,2-c] furan-1,3-dione, 4,4′-oxydiphthalic anhydride (ODPA), 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride ( BTDA), ethylene glycol bisanhydro trimellitate, 4,4'-bi
  • the polyisocyanate (B) of the present embodiment is not particularly limited as long as it is a polyisocyanate generally used in the present technical field.
  • the aliphatic polyisocyanate is not particularly limited.
  • the alicyclic polyisocyanate is not particularly limited.
  • isophorone diisocyanate hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3- Bis (isocyanatomethyl) cyclohexane and the like can be mentioned.
  • the aromatic polyisocyanate is not particularly limited.
  • tolylene diisocyanate 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4 ′ -Dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, metaphenylene bis (isopropyl isocyanate) (TMXDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like.
  • MDI 2,2′-diphenylmethane diisocyanate
  • 2,4′-diphenylmethane diisocyanate 4,4′-diphenylmethane diisocyanate
  • MDI 4,4′-diphenylmethane diisocyanate
  • TMXDI metaphenylene bis
  • the araliphatic polyisocyanate is not particularly limited, and examples thereof include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, ⁇ , ⁇ , ⁇ , ⁇ -tetramethylxylylene diisocyanate.
  • aliphatic polyisocyanate and alicyclic polyisocyanate are preferable, and hexamethylene diisocyanate and isophorone diisocyanate are more preferable from the viewpoint of the effect of improving mechanical strength and mechanical strength.
  • dimers or trimers of these polyisocyanates, and modified products such as bulleted isocyanate can be exemplified. These may be used alone or in combination of two or more.
  • the mixing ratio of (A) acid anhydride and (B) isocyanate compound is not particularly limited.
  • (A) / (B) 100/103 to 100/500 in terms of molar ratio.
  • (A) / (B) 100/150 to 100/300. If it is these ranges, it is preferable from a viewpoint of the mechanical strength, the improvement effect of mechanical strength, and the solubility of a prepolymer.
  • (C) Compound having one or more active hydrogen groups and hydrophilic group>
  • (C) The compound having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited as long as it is a compound having one or more active hydrogen groups and a hydrophilic group.
  • the active hydrogen group is not particularly limited as long as it is reactive with the NCO group, and examples thereof include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH group).
  • the hydrophilic group is not particularly limited, and examples thereof include an anionic hydrophilic group, a cationic hydrophilic group, and a nonionic hydrophilic group.
  • the anionic hydrophilic group is not particularly limited, and examples thereof include a carboxyl group and a salt thereof, a sulfonic acid group and a salt thereof, and the like.
  • the cationic hydrophilic group is not particularly limited, and examples thereof include tertiary ammonium salts and quaternary ammonium salts.
  • the nonionic hydrophilic group is not particularly limited, and examples thereof include a group composed of an ethylene oxide repeating unit and a group composed of an ethylene oxide repeating unit and another alkylene oxide repeating unit. Among these, an anionic hydrophilic group and a nonionic hydrophilic group are preferable.
  • the compound containing one or more active hydrogen groups and a carboxyl group is not particularly limited.
  • 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid In addition to carboxylic acid-containing compounds such as dioxymaleic acid and 3,4-diaminobenzoic acid, derivatives thereof, and salts thereof, polyester polyols obtained using these may be used.
  • amino acids such as alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, and histidine
  • carboxylic acids such as succinic acid, adipic acid, maleic anhydride, phthalic acid, and trimellitic anhydride.
  • 2,2-dimethylolpropionic acid is preferred from the viewpoint of easy emulsification of polyimide.
  • the compound having one or more active hydrogen groups and sulfonic acid groups and salts thereof is not particularly limited, and examples thereof include 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfosulfonic acid.
  • Sulfonic acid-containing compounds such as isophthalic acid, sulfanilic acid, 2-aminoethanesulfonic acid, 1,3-phenylenediamine-4,6-disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid, and derivatives thereof, and examples thereof include polyester polyols, polyamide polyols, and polyamide polyester polyols obtained by copolymerizing these.
  • the aforementioned carboxyl group or sulfonic acid group can be neutralized into a salt to make the finally obtained polyimide water-dispersible.
  • the neutralizing agent in this case is not particularly limited, and examples thereof include non-volatile bases, tertiary amines, and volatile bases.
  • the non-volatile base is not particularly limited, and examples thereof include sodium hydroxide and potassium hydroxide.
  • the tertiary amines are not particularly limited, and examples thereof include trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine.
  • the volatile base is not particularly limited, and examples thereof include ammonia. Neutralization can be performed before, during or after the urethanization reaction.
  • the compound containing one or more active hydrogen groups and a tertiary ammonium salt is not particularly limited, and examples thereof include alkanolamine.
  • the alkanolamine is not particularly limited, and examples thereof include methylaminoethanol and methyldiethanolamine.
  • an organic carboxylic acid such as formic acid or acetic acid, or an inorganic acid such as hydrochloric acid or sulfuric acid to form a salt
  • the polyurethane can be made water-dispersible. Neutralization can be performed before, during or after the urethanization reaction.
  • those obtained by neutralizing methyldiethanolamine with an organic carboxylic acid are preferable.
  • the compound having one or more active hydrogen groups and a quaternary ammonium salt is not particularly limited, and examples thereof include compounds obtained by quaternizing alkanolamines such as methylaminoethanol and methyldiethanolamine with dialkyl sulfuric acid. Can be given.
  • the dialkyl sulfuric acid is not particularly limited, and examples thereof include alkyl halides such as methyl chloride and methyl bromide, dimethyl sulfuric acid, and the like. Among these, from the viewpoint of easy emulsification of polyurethane, a compound obtained by quaternizing methyldiethanolamine with dimethyl sulfate is preferable.
  • the compound having one or more active hydrogen groups and a nonionic hydrophilic group is not particularly limited.
  • polyoxyethylene glycol or polyoxyethylene-polyoxypropylene copolymer glycol polyoxyethylene-polyoxy Nonionic group-containing compounds such as butylene copolymer glycol, polyoxyethylene-polyoxyalkylene copolymer glycol, or monoalkyl ethers thereof, or polyester polyether polyols obtained by copolymerizing these compounds.
  • compounds containing at least 30% by mass of ethylene oxide repeating units and having a number average molecular weight of 300 to 20,000 are preferred.
  • the content of the compound (C) having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited, but is 3 to 15% by mass with respect to the polyimide in the polyimide aqueous dispersion. Preferably, 5 to 10% by mass is more preferable. If it is these ranges, it is preferable from a viewpoint of the improvement effect of mechanical strength and mechanical strength.
  • a catalyst may be used when (A) an acid anhydride, (B) an isocyanate compound, and (C) a polyol having a hydrophilic group are reacted.
  • the catalyst is not particularly limited, and examples thereof include amines, quaternary ammonium salts, imidazoles, amides, pyridines, phosphines, and organometallic salts. From the viewpoint of mechanical strength and the effect of improving mechanical strength, amines and quaternary ammonium salts are more preferable, and quaternary ammonium salts are particularly preferable. Specific examples include triethylamine and tetrabutylammonium bromide.
  • the amount of the catalyst used is not particularly limited, but is preferably 0.005 to 3 parts by weight, more preferably 0.1 to 2 parts by weight with respect to the total weight of the acid anhydride and isocyanate.
  • the acid value of the polyimide in the polyimide aqueous dispersion of the present embodiment is preferably 10 to 100 mgKOH / g, more preferably 20 to 100 mgKOH / g, and further preferably 20 to 60 mgKOH / g. preferable. If it is these ranges, the emulsion stability of polyimide is favorable and it is preferable also from a viewpoint of the improvement effect of mechanical strength and mechanical strength.
  • the acid value of polyimide is calculated from the number of mg of KOH required to neutralize free carboxyl groups contained in 1 g of polyimide solids having carboxyl groups, based on the charged amount of raw materials. Refers to the price.
  • the reaction product of (A) acid anhydride, (B) isocyanate compound, and (C) polyol having a hydrophilic group is further added to (D) polyol (provided that (C) is excluded).
  • the (D) polyol is not particularly limited as long as it is a compound having two or more active hydrogen groups in the molecule.
  • a low molecular weight polyol having a molecular weight of 400 or less a polyester polyol, a polyether polyol, a castor oil-based polyol, a polycarbonate polyol, or a hydrocarbon-based polyol can be used. These can be used alone or in combination of two or more.
  • polyether polyols, polycarbonate polyols, and hydrocarbon-based polyols are preferable from the viewpoint of the effect of improving film formability, mechanical strength, and mechanical strength.
  • the low molecular weight polyol is not particularly limited as long as it has a molecular weight of 400 or less.
  • the polyester polyol is not particularly limited, and examples thereof include a hydroxyl-terminated esterified condensate obtained by reacting the low molecular weight polyol and a polyvalent carboxylic acid.
  • the polyvalent carboxylic acid is not particularly limited.
  • phthalic acid, isophthalic acid and terephthalic acid having an aromatic cyclic structure are preferred from the viewpoint of strength and elastic modulus.
  • the polyether polyol is not particularly limited.
  • the low molecular weight polyol such as bisphenol A and bisphenol F, pentaerythritol, sorbitol, sucrose, or the like obtained by addition polymerization of alkylene oxide, polytetramethylene ether glycol, etc.
  • the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like.
  • those having an aromatic cyclic structure that is, those obtained by addition polymerization of alkylene oxide to bisphenol A and bisphenol F are preferred, and ethylene oxide and / or propylene oxide is added to bisphenol A.
  • Those obtained by addition polymerization are more preferred.
  • the castor oil-based polyol is not particularly limited, and examples thereof include castor oil, hydrogenated castor oil hydrogenated to castor oil, castor oil fatty acid, or polyol produced using hydrogenated castor oil fatty acid hydrogenated thereto. Also included are transesterification products of castor oil and other natural fats and oils, reaction products of castor oil and polyhydric alcohols, esterification reaction products of castor oil fatty acid and polyhydric alcohols, or polyols obtained by addition polymerization of these with alkylene oxide. It is done.
  • the polycarbonate polyol is not particularly limited, and includes conventionally known polycarbonate polyols. Such a polycarbonate polyol is obtained, for example, by a reaction between the low molecular weight polyol and diphenyl carbonate, or a reaction between the low molecular weight polyol and phosgene.
  • the hydrocarbon polyol is not particularly limited, and examples thereof include polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, and hydrogenated polyisoprene polyol.
  • the polyimide aqueous dispersion of the present embodiment is chain-extended.
  • (E) amine can be used for chain extension, and chain extension can be performed by water molecules present in the system at the time of dispersion emulsification in water.
  • (E) amine used for this Embodiment For example, diamine, a polyamine, etc. are mention
  • the diamine is not particularly limited, and examples thereof include ethylene diamine, trimethylene diamine, piperazine, and isophorone diamine.
  • the polyamine is not particularly limited, and examples thereof include diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Of these, ethylenediamine and diethylenetriamine are preferred.
  • the content of the (E) amine in the present embodiment is not particularly limited, but is preferably 0.5 to 2.5% by mass, more preferably 0.7 to 1.5% by mass with respect to the imide prepolymer. preferable.
  • the (C) chain extender is added to the remaining isocyanate groups, and an isocyaninate group and (C) chain extender in the emulsion micelle are subjected to an interfacial polymerization reaction to form a urea bond. Thereby, the crosslinking density in the emulsified micelle is improved, and a three-dimensional crosslinked structure is formed. As described above, the formation of the three-dimensional crosslinked structure can provide excellent mechanical strength and mechanical strength improvement effect.
  • the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. It is also preferable to do this.
  • the method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water, from the viewpoint of improving the mechanical strength and mechanical strength.
  • the method for producing the polyimide aqueous dispersion of the present embodiment is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent.
  • the solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide.
  • These solvents are not particularly limited, and examples thereof include N, N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
  • a crosslinking agent can be used.
  • the crosslinking agent is not particularly limited, and examples thereof include aziridine, oxazoline, carbodiimide, modified polyisocyanate, and polyepoxide compound. These crosslinking agents can be used alone or in combination of two or more.
  • various additives such as a catalyst, an antioxidant, a hygroscopic agent, an antifungal agent, and a silane coupling agent can be added to the polyimide aqueous dispersion of the present embodiment as necessary.
  • the silane coupling agent include alkoxysilanes, vinyl group-containing silane coupling agents, epoxy group-containing silane coupling agents, methacryl group-containing silane coupling agents, and acrylic group-containing silane coupling agents.
  • the storage stability of the polyimide aqueous dispersion of the present embodiment is not particularly limited, but it is preferable that separation and precipitation are not observed in the methods described in the examples.
  • the effect of improving the mechanical strength of the polyimide aqueous dispersion of the present embodiment is not particularly limited, but in the method described in the examples, 100%, 200%, 300%, and the modulus improving effect is 105% or more. Is more preferable, and 120% or more is more preferable.
  • the film strength, 100% modulus, Young's modulus, and elongation of the film obtained from the polyimide aqueous dispersion of the present embodiment are not particularly limited, but in the methods described in the examples, 5 (N / mm 2 ) respectively. 4 (N / mm 2 ), 4 (N / mm 2 ), and preferably 30% or more.
  • Example 1 A four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube is equipped with 10.2 parts by weight of pyromellitic dianhydride (PMDA (manufactured by Daicel)) and 31.1 parts by weight of isophorone diisocyanate (IPDI). Parts, 0.5 parts by weight of tetrabutylammonium bromide and 38.0 parts by weight of N, N-dimethylacetamide (DMAc) and reacted at 120 ° C.
  • PMDA pyromellitic dianhydride
  • IPDI isophorone diisocyanate
  • Examples 2 to 10> The synthesis was performed in the same manner as in Example 1 except that the formulation shown in Table 1 was changed.
  • PMDA pyromellitic dianhydride (Daicel)
  • BTDA Benzophenone tetracarboxylic dianhydride
  • BisMPA dimethylolpropionic acid
  • LBH-P2000 Krasol LBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
  • LBH-P3000 Krasol LBH-P3000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
  • HBH-P2000 Krasol HLBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid hydrogenated polybutadiene)
  • PTMG-2000 (Mitsubishi Chemical, polytetramethylene ether glycol)
  • R-15HT Polybd R-15HT (manufactured by Idemitsu Kosan Co.
  • the aqueous dispersion was put into a Teflon (registered trademark) coating petri dish so as to have a film thickness of 500 ⁇ m, and dried at 80 ° C. for 6 hours, 120 ° C. for 30 minutes, and 150 ° C. for 1 hour to prepare a film.
  • An evaluation sample was prepared by cutting the film into the size of a dumbbell-shaped test piece (No. 3). (Mechanical strength improvement effect)
  • An aqueous dispersion mixed with an aqueous urethane resin Superflex 470, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
  • Obtained polyimide aqueous dispersion 85/15 (weight ratio) was used.
  • the polyimide aqueous dispersion according to the second embodiment is obtained by reacting (A) acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group.
  • the polyimide aqueous dispersion of the present embodiment is an aqueous dispersion and thus has high environmental compatibility, and it is not necessary to use an explosion-proof structure for the equipment used. It also has performance as a binder for electrodes.
  • the (A) acid anhydride of the present embodiment is a carboxylic acid anhydride and is not particularly limited as long as it is a compound obtained by dehydration condensation of two molecules of carboxylic acid.
  • PMDA and BTDA are preferable from the viewpoints of resistance to electrolytic solution and binding.
  • the polyisocyanate (B) of the present embodiment is not particularly limited as long as it is a polyisocyanate generally used in this technical field.
  • an alicyclic polyisocyanate is preferable and isophorone diisocyanate is more preferable from the viewpoint of electrolytic solution resistance and binding properties.
  • the mixing ratio of (A) acid anhydride and (B) isocyanate compound is not particularly limited.
  • (A) / (B) 100/103 to 100/500 in terms of molar ratio.
  • (A) / (B) 100/150 to 100/300.
  • the electrolytic solution resistance and the binding property are good.
  • the compound having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited as long as it is a compound having one or more active hydrogen groups and a hydrophilic group.
  • it may be a compound exemplified in the first embodiment.
  • the compound having one or more active hydrogen groups and a hydrophilic group may be 2,6-dioxybenzoic acid.
  • the content of the compound (C) having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited, but is 3 to 15% by mass with respect to the polyimide in the polyimide aqueous dispersion. Preferably, 5 to 10% by mass is more preferable. If it is these ranges, the emulsion stability of a polyimide is favorable and electrolyte solution resistance is favorable.
  • the acid value of the polyimide in the polyimide aqueous dispersion of the present embodiment is 50 mgKOH / g or less. 5 to 45 mgKOH / g is preferable, and 10 to 40 mgKOH / g is more preferable. If it is these ranges, the emulsification stability of a polyimide is favorable, and it is preferable also from a viewpoint of electrolyte solution resistance and binding property.
  • the acid value of polyimide is calculated from the number of mg of KOH required to neutralize free carboxyl groups contained in 1 g of polyimide solids having carboxyl groups, based on the charged amount of raw materials. Refers to the price.
  • the reaction product of (A) acid anhydride, (B) isocyanate compound, and (C) polyol having a hydrophilic group is further added to (D) polyol (provided that (C) is excluded).
  • the (D) polyol is not particularly limited as long as it is a compound having two or more active hydrogen groups in the molecule.
  • a low molecular weight polyol having a molecular weight of 400 or less a polyester polyol, a polyether polyol, a castor oil-based polyol, a polycarbonate polyol, or a hydrocarbon-based polyol can be used. These can be used alone or in combination of two or more.
  • polyether polyols and hydrocarbon polyols are preferable from the viewpoint of resistance to electrolytic solution and binding properties.
  • the polyimide aqueous dispersion of the present embodiment is chain-extended.
  • (E) amine can be used for chain extension, and chain extension can be performed by water molecules present in the system at the time of dispersion emulsification in water. Of these, amine elongation is preferable from the viewpoint of resistance to electrolytic solution and binding.
  • the (E) amine used in the present embodiment is not particularly limited, and examples thereof include diamines and polyamines exemplified in the first embodiment. Of these, ethylenediamine and diethylenetriamine are preferred.
  • the content of (E) amine in the present embodiment is not particularly limited, but is preferably 0.5 to 2.5% by mass, and 0.7 to 1.5% by mass with respect to the imide prepolymer. If so, the electrolytic solution resistance and the binding property are particularly excellent.
  • the (C) chain extender is added to the remaining isocyanate groups, and an isocyaninate group and (C) chain extender in the emulsion micelle are subjected to an interfacial polymerization reaction to form a urea bond. Thereby, the crosslinking density in the emulsified micelle is improved, and a three-dimensional crosslinked structure is formed. Thus, by forming a three-dimensional crosslinked structure, excellent electrolytic solution resistance and binding properties can be obtained.
  • the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. Is also preferable.
  • the method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water from the viewpoint of the electrolytic solution resistance and binding properties of the product.
  • the production method of the polyimide aqueous dispersion of the present invention is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent.
  • the solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide.
  • These solvents are not particularly limited, and examples thereof include N, N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
  • the polyimide aqueous dispersion of the present embodiment can be used as a binder for an electrode of a lithium secondary battery because the resulting film has good electrolytic solution resistance and binding properties.
  • a binder the polyimide water dispersion of this Embodiment can also be used independently, and another binder can also be used together.
  • the other binder is not particularly limited, but polyvinylidene fluoride, polyvinylidene fluoride copolymer resin, fluorine resin, styrene-butadiene rubber, ethylene-propylene rubber, styrene-acrylonitrile copolymer, acrylic copolymer.
  • One or more (Y) selected from the group consisting of a coalescence and an aqueous dispersion of urethane resin is preferred.
  • aqueous dispersions of styrene-butadiene rubber and urethane resin are preferred.
  • the electrode binder for the lithium secondary battery of this embodiment can also be used for an electrode.
  • the binder of this embodiment can be used for both the positive electrode and the negative electrode.
  • the electrode of the present embodiment is not particularly limited as long as it uses an electrode binder, but the electrode active material, the conductive agent, the electrode active material, and the binder that binds the conductive agent to the current collector. Etc.
  • the positive electrode active material used for the positive electrode of the lithium secondary battery of this embodiment is not particularly limited as long as it can insert and desorb lithium ions.
  • CuO, Cu 2 O, MnO 2 , MoO 3 , V 2 O 5 , CrO 3 , MoO 3 , Fe 2 O 3, Ni 2 O 3, CoO 3 and other metal oxides LixCoO 2 , LixNiO 2 , LixMn 2 O 4 , composite oxides of lithium and transition metals such as LiFePO 4 , metal chalcogenides such as TiS 2 , MoS 2 , and NbSe 3 , conductive polymer compounds such as polyacene, polyparaphenylene, polypyrrole, and polyaniline It is done.
  • a composite oxide of lithium and at least one selected from transition metals such as cobalt, nickel and manganese which is generally called a high voltage system, is capable of obtaining lithium ion release properties and high voltage.
  • transition metals such as cobalt, nickel and manganese
  • LiFePO 4 , LiMn 2 O 4 , and LiNixCo (1-x) O 2 are preferable. Two or more kinds of the positive electrode active materials can be used in combination.
  • the negative electrode active material used for the negative electrode of the lithium secondary battery of the present embodiment is not particularly limited as long as it can insert and desorb metallic lithium or lithium ions.
  • Examples thereof include carbon materials, metal materials, lithium transition metal nitrides, crystalline metal oxides, amorphous metal oxides, silicon compounds, and conductive polymers.
  • the carbon material is not particularly limited, and examples thereof include natural graphite, artificial graphite, non-graphitizable carbon, and graphitizable carbon.
  • metallic lithium, an alloy, a tin compound etc. are mention
  • Specific examples include Li 4 Ti 5 O 12 and NiSi 5 C 6 . Of these, natural graphite, SiO, and Li 4 Ti 5 O 12 are preferable.
  • any electronic conductive material that does not adversely affect the battery performance can be used without particular limitation.
  • carbon black such as acetylene black and kettin black is used, but natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon whisker, carbon fiber and metal (copper, nickel, aluminum)
  • conductive materials such as powder, metal fibers, and conductive ceramic materials can be used. These can also be used as a mixture of two or more. Of these, carbon black is preferred.
  • the addition amount is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass with respect to the amount of active material.
  • any electronic conductor that does not adversely affect the constructed battery can be used without particular limitation.
  • a positive electrode current collector aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer, conductive glass, etc., in addition to aluminum for the purpose of improving adhesiveness, conductivity, and oxidation resistance.
  • a material obtained by treating the surface of copper or copper with carbon, nickel, titanium, silver or the like can be used.
  • the current collector for negative electrode copper, stainless steel, nickel, aluminum, titanium, calcined carbon, conductive polymer, conductive glass, Al—Cd alloy, etc., adhesiveness, conductivity, oxidation resistance
  • adhesiveness, conductivity, oxidation resistance it is possible to use a surface of copper or the like treated with carbon, nickel, titanium, silver or the like.
  • the surface of these current collector materials can be oxidized.
  • molded bodies such as a film form, a sheet form, a net form, the punched or expanded thing, a lath body, a porous body, and a foam other than foil shape, are also used.
  • the thickness is not particularly limited, but a thickness of 1 to 100 ⁇ m is usually used.
  • the electrode of the lithium secondary battery of this embodiment is a mixture of an electrode active material, a conductive agent, a current collector of the electrode active material, and a binder that binds the electrode active material and the conductive agent to the current collector. Then, a slurry-like electrode material is prepared and applied to an aluminum foil or a copper foil as a current collector, and the dispersion medium is volatilized to produce the electrode material.
  • a thickener such as a water-soluble polymer can be used as a viscosity modifier for slurrying.
  • celluloses such as carboxymethylcellulose salt, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylmethylcellulose; polycarboxylic acid compounds such as polyacrylic acid and polyacrylic acid soda; vinylpyrrolidone such as polyvinylpyrrolidone Compound having structure: One or more selected from polyacrylamide, polyethylene oxide, polyvinyl alcohol, sodium alginate, xanthan gum, carrageenan, guar gum, agar, starch, etc. can be used, among which carboxymethyl cellulose salt is preferred .
  • the method and order of mixing the electrode materials are not particularly limited.
  • the active material and the conductive agent can be mixed and used in advance.
  • a mortar, a mill mixer, a planetary ball mill can be used.
  • a ball mill such as a shaker type ball mill, a mechano-fusion, or the like can be used.
  • the lithium secondary battery of the present embodiment is configured using an electrode using a binder for an electrode of a lithium secondary battery using a polyimide aqueous dispersion.
  • the electrode using the binder for electrodes of the lithium secondary battery may be used for at least one of the positive electrode and the negative electrode.
  • the lithium secondary battery of the present embodiment is not particularly limited.
  • a positive electrode and a negative electrode, a separator provided between the positive electrode and the negative electrode and isolating both, and a supporting electrolyte in a solvent for conducting lithium ions As a non-aqueous electrolyte solution in which a lithium salt is dissolved and an electrolyte layer containing a polymer or a polymer gel electrolyte.
  • the separator used in the lithium secondary battery according to the present embodiment is not particularly limited as long as it is a separator used in a normal lithium secondary battery, and is made of, for example, polyethylene, polypropylene, polyolefin, polytetrafluoroethylene, or the like. Examples thereof include porous resins, ceramics, and nonwoven fabrics.
  • an organic electrolytic solution and an ionic liquid that have been conventionally used in lithium secondary batteries can be used without particular limitation.
  • an electrolytic solution salts used in the lithium secondary battery of the present embodiment is not particularly limited, for example, LiPF 6, LiBF 4, LiClO 4, LiAsF 6, LiCl, LiBr, LiCF 3 SO 3, LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiI, LiAlCl 4 , NaClO 4 , NaBF 4 , NaI and the like can be mentioned, and in particular, inorganic lithium such as LiPF 6 , LiBF 4 , LiClO 4 and LiAsF 6 salts, and organic lithium salt represented by LiN (SO 2 CxF 2 x +1 ) (SO 2 CyF 2y + 1).
  • x and y represent 0 or an integer of 1 to 4, and x + y is an integer of 2 to 8.
  • the organic lithium salt LiN (SO 2 F) 2 , LiN (SO 2 CF 3 ) (SO 2 C 2 F 5 ), LiN (SO 2 CF 3 ) (SO 2 C 3 F 7 ) LiN (SO 2 CF 3 ) (SO 2 C 4 F 9 ), LiN (SO 2 C 2 F 5 ) 2 , LiN (SO 2 C 2 F 5 ) (SO 2 C 3 F 7 ), LiN (SO 2 C 2 F 5 ) (SO 2 C 4 F 9 ) and the like.
  • LiPF 6 LiBF 4 , LiN (CF 3 SO 2 ) 2 , LiN (SO 2 F) 2 , LiN (SO 2 C 2 F 5 ) 2 or the like as the electrolyte because it has excellent electrical characteristics.
  • the said electrolyte salt can also be used individually by 1 type, and can also be used 2 or more types.
  • Such a lithium salt is desirably contained in the electrolytic solution at a concentration of usually 0.1 to 2.0 mol / liter, preferably 0.3 to 1.5 mol / liter.
  • the organic solvent for dissolving the electrolyte salt of the lithium secondary battery of the present embodiment is not particularly limited as long as it is an organic solvent used for a non-aqueous electrolyte of a normal lithium secondary battery.
  • organic solvent used for a non-aqueous electrolyte of a normal lithium secondary battery.
  • the carbonates are not particularly limited, and examples include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethylene glycol dimethyl carbonate, propylene glycol dimethyl carbonate, ethylene glycol diethyl carbonate, vinylene carbonate, and the like.
  • the lactone is not particularly limited, and examples thereof include ⁇ -butyrolactone.
  • the ethers are not particularly limited, and examples thereof include dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like.
  • the sulfolanes are not particularly limited, and examples thereof include sulfolane and 3-methylsulfolane.
  • the dioxolanes are not particularly limited, and examples thereof include 1,3-dioxolane.
  • the ketones are not particularly limited, and examples thereof include 4-methyl-2-pentanone.
  • the nitriles are not particularly limited, and examples thereof include acetonitrile, propionitrile, valeronitrile, and benzonitrile.
  • the halogenated hydrocarbons are not particularly limited, and examples thereof include 1,2-dichloroethane.
  • the ionic liquid is not particularly limited, and examples thereof include methyl formate, dimethylformamide, diethylformamide, dimethyl sulfoxide, imidazolium salt, and quaternary ammonium salt.
  • These organic solvents can be used alone or in combination of two or more.
  • a polymer electrolyte or a polymer gel electrolyte when a polymer electrolyte or a polymer gel electrolyte is used, ether, ester, siloxane, acrylonitrile, vinylidene fluoride, hexafluoropropylene, acrylate, methacrylate, styrene, vinyl acetate, vinyl chloride
  • a polymer such as oxetane or a polymer having a copolymer structure thereof or a polymer compound such as a cross-linked product thereof is used, and these can be used alone or in combination of two or more.
  • a polymer compound having an ether structure such as polyethylene oxide is more preferable.
  • the liquid battery is an electrolyte
  • the gel battery is a precursor solution in which a polymer is dissolved in the electrolyte
  • the solid electrolyte battery is a polymer before crosslinking in which an electrolyte salt is dissolved.
  • the lithium secondary battery of this embodiment can be formed in a cylindrical shape, a coin shape, a square shape, or any other shape, and the basic configuration of the battery is the same regardless of the shape, and the design can be changed according to the purpose Can be implemented.
  • a wound body in which a negative electrode formed by applying a negative electrode active material to a negative electrode current collector and a positive electrode formed by applying a positive electrode active material to a positive electrode current collector are wound through a separator. It is housed in a battery can, sealed with a non-aqueous electrolyte injected, and insulating plates placed on top and bottom.
  • a disc-shaped negative electrode, a separator, a disc-shaped positive electrode, and a stainless steel plate are stacked and stored in a coin-type battery can, and a non-aqueous electrolyte is injected, Sealed.
  • the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. It is also preferable to do this.
  • the method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water from the viewpoint of resistance to electrolytic solution and binding.
  • the method for producing the polyimide aqueous dispersion of the present embodiment is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent.
  • the solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide.
  • These solvents are not particularly limited, and examples thereof include dimethylacetamide and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
  • a crosslinking agent can be used.
  • the crosslinking agent is not particularly limited, and examples thereof include aziridine, oxazoline, carbodiimide, modified polyisocyanate, and polyepoxide compound. These crosslinking agents can be used alone or in combination of two or more.
  • the electrolytic solution resistance of the film formed from the polyimide aqueous dispersion of the present embodiment is preferably 1000% or less, more preferably 750% or less, and 500%. More preferably, it is as follows.
  • the binding property of the film formed from the polyimide aqueous dispersion of the present embodiment is preferably 0.30 N / cm or more and preferably 0.35 N / cm or more in the method described in the examples. More preferably, it is more preferably 0.40 N / cm or more.
  • Example 1 A four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube is equipped with 10.2 parts by weight of pyromellitic dianhydride (PMDA (manufactured by Daicel)) and 31.1 parts by weight of isophorone diisocyanate (IPDI). Parts, 0.5 parts by weight of tetrabutylammonium bromide and 38.0 parts by weight of N, N-dimethylacetamide (DMAc) and reacted at 120 ° C.
  • PMDA pyromellitic dianhydride
  • IPDI isophorone diisocyanate
  • Examples 2 to 7, Comparative Example> The synthesis was performed in the same manner as in Example 1 except that the formulation shown in Table 3 was changed.
  • PMDA pyromellitic dianhydride (Daicel)
  • BTDA Benzophenone tetracarboxylic dianhydride
  • BisMPA dimethylolpropionic acid
  • LBH-P2000 Krasol LBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
  • LBH-P3000 Krasol LBH-P3000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
  • HBH-P2000 Krasol HLBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid hydrogenated polybutadiene)
  • PTMG-2000 (Mitsubishi Chemical, polytetramethylene ether glycol)
  • R-15HT Polybd R-15HT (manufactured by Idemitsu Kosan Co.
  • ⁇ Evaluation method> (Electrolytic solution resistance)
  • the polyimide aqueous dispersion was preliminarily dried at 40 ° C. for 8 hours, and then finally dried in the order of 80 ° C. for 6 hours, 120 ° C. for 1 hour, 150 ° C. for 30 minutes, and a test piece having a thickness of 2 cm ⁇ 2 cm and a film thickness of 500 ⁇ m.
  • the obtained test piece was added to a carbonate mixed solvent (composition with a weight ratio of 1: 1: 1: 1: 1) consisting of five kinds of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.
  • Example 2 carboxymethylcellulose (CMC) (Daiichi Kogyo Seiyaku Co., Ltd., product name: Serogen WS-C) 2 wt% aqueous solution 175.0 g as a thickener, polyimide aqueous dispersion synthesized in Example 1 as a binder ( (Nonvolatile content: 31.6%) 11.1 g was mixed with a planetary mixer to prepare a negative electrode slurry. This negative electrode slurry was coated on an electrolytic copper foil having a thickness of 10 ⁇ m by a coating machine, dried at 120 ° C., and then subjected to a roll press treatment, to obtain a negative electrode having a negative electrode active material of 7 mg / cm 2 .
  • CMC carboxymethylcellulose
  • Serogen WS-C Serogen WS-C
  • the electrode prepared above was dried under reduced pressure at 130 ° C. for 8 hours, and after pressing, a 180 ° peel peel strength test was performed based on JIS Z0237: 2009.
  • a test piece affixed to a SUS304 steel plate with a general-purpose adhesive tape cut to a width of 18 mm and a length of 300 mm was gripped on the end of the tape so that the back surface of the tape overlapped, folded back to 180 °, and peeled off from the test plate by 25 mm Later, one end of the test plate where the tape was peeled off was fixed to the lower jig installed in the testing machine, and the adhesive tape was fixed to the upper jig.
  • the test is carried out at a load speed of 50 mm / min. After starting the measurement, the measurement value for the first 25 mm is ignored, and after 25 mm has elapsed, the average value of the peel-off adhesive strength when the test plate is peeled off is measured. did.

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Abstract

The objective of the present invention is to provide an aqueous polyimide dispersion that has high environmental suitability because of being an aqueous dispersion and does not require a facility, in which the aqueous polyimide dispersion is used, to have an explosion-proof structure, while forming a film that has good physical properties. The present invention relates to an aqueous polyimide dispersion which is obtained by reacting (A) an acid anhydride, (B) a polyisocyanate and (C) a compound having one or more active hydrogen groups and a hydrophilic group. The present invention also relates to a method for producing an aqueous polyimide dispersion, which comprises: a step for synthesizing a prepolymer by reacting (A) an acid anhydride, (B) a polyisocyanate and (C) a compound having one or more active hydrogen groups and a hydrophilic group; and a step for emulsifying the prepolymer in water.

Description

ポリイミド水分散体、電極用結着剤、電極、二次電池およびポリイミド水分散体の製造方法Polyimide aqueous dispersion, electrode binder, electrode, secondary battery, and method for producing polyimide aqueous dispersion
　本発明は、ポリイミド水分散体、電極用結着剤、電極、二次電池およびポリイミド水分散体の製造方法に関する。 The present invention relates to a polyimide aqueous dispersion, an electrode binder, an electrode, a secondary battery, and a method for producing a polyimide aqueous dispersion.
　ポリイミドは幅広い用途で使用されている。例えば、リチウムイオン二次電池用負極への使用について開示されている（特許文献１）。一方、ポリイソシアネートを用い、無溶媒下で得られる熱硬化性ウレタンイミド組成物について開示されている（特許文献２）。 Polyimide is used in a wide range of applications. For example, the use to the negative electrode for lithium ion secondary batteries is disclosed (patent document 1). On the other hand, a thermosetting urethane imide composition obtained by using polyisocyanate and without solvent is disclosed (Patent Document 2).
特開２００２－３７８４８号公報JP 2002-37848 A 特開２０１５－２２０２２１号公報Japanese Patent Laid-Open No. 2015-220221
　しかし、特許文献１の方法では使用設備を防爆構造等にする必要があり、改善が望まれていた。また、機械強度の改善効果も大きなポリイミドが求められていた。 However, in the method of Patent Document 1, it is necessary to use an explosion-proof structure for the equipment used, and improvement has been desired. In addition, a polyimide having a great effect of improving the mechanical strength has been demanded.
　本発明の発明者らは、上記課題を解決すべくポリイミドの水分散体に着目し、検討を行った。水分散体とすることで、環境適合性が高く、使用設備を防爆構造等にする必要がなく、また機械強度の改善効果も大きなものとなる。鋭意検討を重ねた結果、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応して得られるポリイミド水分散体を用いることにより、上記課題を解決できることを見いだし、本発明を完成させるに至った。 The inventors of the present invention paid attention to an aqueous dispersion of polyimide in order to solve the above-mentioned problems and studied. By using an aqueous dispersion, the environmental compatibility is high, it is not necessary to make the equipment used an explosion-proof structure, and the effect of improving the mechanical strength is great. As a result of extensive studies, (A) an acid anhydride, (B) polyisocyanate, and (C) a polyimide aqueous dispersion obtained by reacting one or more active hydrogen groups and a compound having a hydrophilic group are used. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.
　すなわち、本発明は下記に掲げるに発明に関する。
　（１）　（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応して得られるポリイミド水分散体。
　（２）　ポリイミドの酸価が、２０～１００ｍｇＫＯＨ／ｇである（１）記載のポリイミド水分散体。
　（３）　（１）または（２）記載のポリイミド水分散体を鎖伸長して得られるポリイミド水分散体。
　（４）　酸価が５０ｍｇＫＯＨ／ｇ以下である、（１）記載のポリイミド水分散体。
　（５）　（Ｅ）アミンを用いて鎖伸長して得られる（４）記載のポリイミド水分散体。
　（６）　（４）または（５）記載のポリイミド水分散体を用いたリチウム二次電池の電極用結着剤。
　（７）　（６）記載のリチウム二次電池の電極用結着剤を用いた電極。
　（８）　（７）記載の電極を有するリチウム二次電池。
　（９）　（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応させプレポリマーを合成する工程と、プレポリマーを水中で乳化する工程と、を含むポリイミド水分散体の製造方法。
　（１０）　さらに鎖伸長する工程を含む（９）記載のポリイミド水分散体の製造方法。
　（１１）　酸価が２０～１００ｍｇＫＯＨ／ｇである、（９）または（１０）記載のポリイミド水分散体の製造方法。
　（１２）　酸価が５０ｍｇＫＯＨ／ｇ以下である、（９）または（１０）記載のポリイミド水分散体の製造方法。 That is, the present invention relates to the invention described below.
(1) A polyimide aqueous dispersion obtained by reacting (A) an acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group.
(2) The polyimide aqueous dispersion according to (1), wherein the acid value of the polyimide is 20 to 100 mgKOH / g.
(3) A polyimide aqueous dispersion obtained by chain elongation of the polyimide aqueous dispersion described in (1) or (2).
(4) The polyimide water dispersion as described in (1) whose acid value is 50 mgKOH / g or less.
(5) The polyimide aqueous dispersion according to (4), obtained by chain elongation using (E) amine.
(6) A binder for an electrode of a lithium secondary battery using the polyimide aqueous dispersion according to (4) or (5).
(7) The electrode using the binder for electrodes of the lithium secondary battery as described in (6).
(8) A lithium secondary battery having the electrode according to (7).
(9) (A) acid anhydride, (B) polyisocyanate, and (C) a step of synthesizing one or more active hydrogen groups and a compound having a hydrophilic group to synthesize a prepolymer, and emulsifying the prepolymer in water A process for producing a polyimide aqueous dispersion.
(10) The method for producing a polyimide aqueous dispersion according to (9), further comprising a step of chain elongation.
(11) The method for producing an aqueous polyimide dispersion according to (9) or (10), wherein the acid value is 20 to 100 mgKOH / g.
(12) The method for producing a polyimide aqueous dispersion according to (9) or (10), wherein the acid value is 50 mgKOH / g or less.
　本発明のポリイミド水分散体は水分散体であることから環境適合性が高く、使用設備を防爆構造等にする必要もない。また、機械強度の改善効果も大きい。 Since the polyimide aqueous dispersion of the present invention is an aqueous dispersion, it has high environmental compatibility, and there is no need to make the equipment used an explosion-proof structure. Moreover, the improvement effect of mechanical strength is also great.
［第1の実施の形態］
　まず、本発明の第1の実施の形態のポリイミド水分散体について説明する。本実施の形態のポリイミド水分散体は、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応して得られる。 [First embodiment]
First, the polyimide aqueous dispersion according to the first embodiment of the present invention will be described. The polyimide aqueous dispersion of the present embodiment is obtained by reacting (A) acid anhydride, (B) polyisocyanate, and (C) one or more active hydrogen groups and a compound having a hydrophilic group.
　＜（Ａ）酸無水物＞
　本実施の形態の（Ａ）酸無水物としては、カルボン酸無水物をいい、２分子のカルボン酸を脱水縮合させた化合物であれば特に限定されるものではない。例えば、１，２，３，４－ブタンテトラカルボン酸二無水物、無水ピロメリット酸（ＰＭＤＡ）、１，３，３ａ，４，５，９ｂ－ヘキサヒドロ－５（テトラヒドロ－２，５－ジオキソ－３－フラニル）ナフト［１，２－ｃ］フラン－１，３－ジオン、４，４′－オキシジフタル酸無水物（ＯＤＰＡ）、３，３′，４，４′－ベンゾフェノンテトラカルボン酸無水物（ＢＴＤＡ）、エチレングリコール ビスアンヒドロトリメリテート、４，４′－ビフタル酸無水物（ＢｉＰＡ）、３，３′，４，４′－ジフェニルスルホンテトラカルボン酸無水物（ＤＰＳＡ）、等があげられる。これらは単独でもしくは２種以上併せて用いられる。特に限定されないが、これらのうち、機械強度、機械強度の改善効果の観点から、ＰＭＤＡ、ＢＴＤＡが好ましい。 <(A) Acid anhydride>
The (A) acid anhydride of the present embodiment is a carboxylic acid anhydride and is not particularly limited as long as it is a compound obtained by dehydration condensation of two molecules of carboxylic acid. For example, 1,2,3,4-butanetetracarboxylic dianhydride, pyromellitic anhydride (PMDA), 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo- 3-furanyl) naphtho [1,2-c] furan-1,3-dione, 4,4′-oxydiphthalic anhydride (ODPA), 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride ( BTDA), ethylene glycol bisanhydro trimellitate, 4,4'-biphthalic anhydride (BiPA), 3,3 ', 4,4'-diphenylsulfone tetracarboxylic anhydride (DPSA), etc. . These may be used alone or in combination of two or more. Among these, PMDA and BTDA are preferable from the viewpoints of mechanical strength and mechanical strength improvement effect.
　＜（Ｂ）ポリイソシアネート＞
　本実施の形態の（Ｂ）ポリイソシアネートとしては、本技術分野で一般的に使用されるポリイソシアネートであれば特に限定されるものではないが、例えば、脂肪族ポリイソシアネート、脂環族ポリイソシアネート、芳香族ポリイソシアネート、芳香脂肪族ポリイソシアネート、（Ｂ１）ブロックイソシアネート化合物などをあげることができる。 <(B) Polyisocyanate>
The polyisocyanate (B) of the present embodiment is not particularly limited as long as it is a polyisocyanate generally used in the present technical field. For example, aliphatic polyisocyanate, alicyclic polyisocyanate, Examples thereof include aromatic polyisocyanates, araliphatic polyisocyanates, and (B1) blocked isocyanate compounds.
　前記、脂肪族ポリイソシアネートとしては特に限定されないが、例えば、テトラメチレンジイソシアネート、ドデカメチレンジイソシアネート、ヘキサメチレンジイソシアネート、２，２，４－トリメチルヘキサメチレンジイソシアネート、２，４，４－トリメチルヘキサメチレンジイソシアネート、リジンジイソシアネート、２－メチルペンタン－１，５－ジイソシアネート、３－メチルペンタン－１，５－ジイソシアネートなどをあげることができる。 The aliphatic polyisocyanate is not particularly limited. For example, tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine Examples thereof include diisocyanate, 2-methylpentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.
　前記、脂環族ポリイソシアネートとしては特に限定されないが、例えば、イソホロンジイソシアネート、水添キシリレンジイソシアネート、４，４’－ジシクロヘキシルメタンジイソシアネート、１，４－シクロヘキサンジイソシアネート、メチルシクロヘキシレンジイソシアネート、１，３－ビス（イソシアネートメチル）シクロヘキサンなどをあげることができる。 The alicyclic polyisocyanate is not particularly limited. For example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3- Bis (isocyanatomethyl) cyclohexane and the like can be mentioned.
　前記、芳香族ポリイソシアネートとしては特に限定されないが、例えば、トリレンジイソシアネート、２，２’－ジフェニルメタンジイソシアネート、２，４’－ジフェニルメタンジイソシアネート、４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）、４，４’－ジベンジルジイソシアネート、１，５－ナフチレンジイソシアネート、キシリレンジイソシアネート、メタフェニレンビス(イソプロピルイソシアナート)（ＴＭＸＤＩ）、１，３－フェニレンジイソシアネート、１，４－フェニレンジイソシアネートなどをあげることができる。 The aromatic polyisocyanate is not particularly limited. For example, tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4 ′ -Dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, metaphenylene bis (isopropyl isocyanate) (TMXDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like.
　前記、芳香脂肪族ポリイソシアネートとしては特に限定されないが、例えば、ジアルキルジフェニルメタンジイソシアネート、テトラアルキルジフェニルメタンジイソシアネート、α，α，α，α－テトラメチルキシリレンジイソシアネートなどをあげることができる。 The araliphatic polyisocyanate is not particularly limited, and examples thereof include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene diisocyanate.
　これらのうち、機械強度、機械強度の改善効果の観点から、脂肪族ポリイソシアネート、脂環族ポリイソシアネートが好ましく、ヘキサメチレンジイソシアネート、イソホロンジイソシアネートがより好ましい。 Of these, aliphatic polyisocyanate and alicyclic polyisocyanate are preferable, and hexamethylene diisocyanate and isophorone diisocyanate are more preferable from the viewpoint of the effect of improving mechanical strength and mechanical strength.
　また、これらのポリイソシアネートの２量体又は３量体や、ビュレット化イソシアネート等の変性体を挙げることができる。これらは１種または２種以上を併用することもできる。 In addition, dimers or trimers of these polyisocyanates, and modified products such as bulleted isocyanate can be exemplified. These may be used alone or in combination of two or more.
　本実施の形態において、（Ａ）酸無水物と（Ｂ）イソシアネート化合物の混合割合は、特に限定されないが、例えば、モル比で、（Ａ）／（Ｂ）＝１００／１０３～１００／５００が好ましく、より好ましくは（Ａ）／（Ｂ）＝１００／１５０～１００／３００である。これらの範囲であれば、機械強度、機械強度の改善効果およびプレポリマーの溶解性の観点から、好ましい。 In the present embodiment, the mixing ratio of (A) acid anhydride and (B) isocyanate compound is not particularly limited. For example, (A) / (B) = 100/103 to 100/500 in terms of molar ratio. Preferably, (A) / (B) = 100/150 to 100/300. If it is these ranges, it is preferable from a viewpoint of the mechanical strength, the improvement effect of mechanical strength, and the solubility of a prepolymer.
　＜（Ｃ）１個以上の活性水素基と親水基を有する化合物＞
　本実施の形態の（Ｃ）１個以上の活性水素基と親水基を有する化合物としては、１個以上の活性水素基と親水性基を有する化合物であれば特に限定されるものではない。 <(C) Compound having one or more active hydrogen groups and hydrophilic group>
(C) The compound having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited as long as it is a compound having one or more active hydrogen groups and a hydrophilic group.
　前記、活性水素基としてはＮＣＯ基と反応性を有するものであれば、特に限定されないが、例えば、水酸基、第１級又は第２級アミノ基、チオール基（ＳＨ基）などがあげられる。前記、親水性基としては、特に限定されないが、例えば、アニオン性親水基、カチオン性親水基、ノニオン性親水基などがあげられる。前記、アニオン性親水基としては、特に限定されないが、例えば、カルボキシル基及びその塩、スルホン酸基及びその塩などがあげられる。前記、カチオン性親水基としては、特に限定されないが、例えば、第三級アンモニウム塩、第四級アンモニウム塩などがあげられる。前記、ノニオン性親水基としては、特に限定されないが、例えば、エチレンオキシドの繰り返し単位からなる基や、エチレンオキシドの繰り返し単位とその他のアルキレンオキシドの繰り返し単位からなる基などがあげられる。これらのうち、アニオン性親水基、ノニオン性親水基が好ましい。 The active hydrogen group is not particularly limited as long as it is reactive with the NCO group, and examples thereof include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH group). The hydrophilic group is not particularly limited, and examples thereof include an anionic hydrophilic group, a cationic hydrophilic group, and a nonionic hydrophilic group. The anionic hydrophilic group is not particularly limited, and examples thereof include a carboxyl group and a salt thereof, a sulfonic acid group and a salt thereof, and the like. The cationic hydrophilic group is not particularly limited, and examples thereof include tertiary ammonium salts and quaternary ammonium salts. The nonionic hydrophilic group is not particularly limited, and examples thereof include a group composed of an ethylene oxide repeating unit and a group composed of an ethylene oxide repeating unit and another alkylene oxide repeating unit. Among these, an anionic hydrophilic group and a nonionic hydrophilic group are preferable.
　前記、１個以上の活性水素基とカルボキシル基を含有する化合物としては、特に限定されないが、例えば、２，２－ジメチロールプロピオン酸、２，２－ジメチロール酪酸、２，２－ジメチロール吉草酸、ジオキシマレイン酸、３，４－ジアミノ安息香酸等のカルボン酸含有化合物及びこれらの誘導体並びにそれらの塩に加え、これらを使用して得られるポリエステルポリオールなどがあげられる。更に、アラニン、アミノ酪酸、アミノカプロン酸、グリシン、グルタミン酸、アスパラギン酸、ヒスチジン等のアミノ酸類、コハク酸、アジピン酸、無水マレイン酸、フタル酸、無水トリメリット酸等のカルボン酸類などがあげられる。これらのうち、ポリイミドの乳化の容易性の観点からは、２，２－ジメチロールプロピオン酸が好ましい。 The compound containing one or more active hydrogen groups and a carboxyl group is not particularly limited. For example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, In addition to carboxylic acid-containing compounds such as dioxymaleic acid and 3,4-diaminobenzoic acid, derivatives thereof, and salts thereof, polyester polyols obtained using these may be used. Further examples include amino acids such as alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, and histidine, and carboxylic acids such as succinic acid, adipic acid, maleic anhydride, phthalic acid, and trimellitic anhydride. Of these, 2,2-dimethylolpropionic acid is preferred from the viewpoint of easy emulsification of polyimide.
　前記、１個以上の活性水素基とスルホン酸基及びその塩を有する化合物としては、特に限定されないが、例えば、２－オキシエタンスルホン酸、フェノールスルホン酸、スルホ安息香酸、スルホコハク酸、５－スルホイソフタル酸、スルファニル酸、2-アミノエタンスルホン酸、１，３－フェニレンジアミン－４，６－ジスルホン酸、２，４－ジアミノトルエン－５－スルホン酸等のスルホン酸含有化合物及びこれらの誘導体、並びにこれらを共重合して得られるポリエステルポリオール、ポリアミドポリオール、ポリアミドポリエステルポリオールなどがあげられる。 The compound having one or more active hydrogen groups and sulfonic acid groups and salts thereof is not particularly limited, and examples thereof include 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfosulfonic acid. Sulfonic acid-containing compounds such as isophthalic acid, sulfanilic acid, 2-aminoethanesulfonic acid, 1,3-phenylenediamine-4,6-disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid, and derivatives thereof, and Examples thereof include polyester polyols, polyamide polyols, and polyamide polyester polyols obtained by copolymerizing these.
　前記、カルボキシル基又はスルホン酸基は、中和して塩にすることにより、最終的に得られるポリイミドを水分散性にすることができる。この場合の中和剤としては、特に限定されないが、例えば、不揮発性塩基、第三級アミン類、揮発性塩基などがあげられる。前記、不揮発性塩基としては、特に限定されないが、例えば水酸化ナトリウム、水酸化カリウムなどがあげられる。前記、第三級アミン類としては、特に限定されないが、例えば、トリメチルアミン、トリエチルアミン、ジメチルエタノールアミン、メチルジエタノールアミン、トリエタノールアミンなどがあげられる。前記、揮発性塩基としては、特に限定されないが、例えば、アンモニアなどがあげられる。中和は、ウレタン化反応前、反応中、又は反応後の何れにおいても行うことができる。 The aforementioned carboxyl group or sulfonic acid group can be neutralized into a salt to make the finally obtained polyimide water-dispersible. The neutralizing agent in this case is not particularly limited, and examples thereof include non-volatile bases, tertiary amines, and volatile bases. The non-volatile base is not particularly limited, and examples thereof include sodium hydroxide and potassium hydroxide. The tertiary amines are not particularly limited, and examples thereof include trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine. The volatile base is not particularly limited, and examples thereof include ammonia. Neutralization can be performed before, during or after the urethanization reaction.
　前記、１個以上の活性水素基と第３級アンモニウム塩を含有する化合物としては、特に限定されないが、例えば、アルカノールアミンなどがあげられる。前記、アルカノールアミンとしては、特に限定されないが、例えば、メチルアミノエタノール、メチルジエタノールアミンなどがあげられる。これらを、ギ酸、酢酸などの有機カルボン酸、塩酸、硫酸などの無機酸で中和して塩にすることによりポリウレタンを水分散性にすることができる。中和は、ウレタン化反応前、反応中、又は反応後の何れにおいても行うことができる。これらのうち、ポリイミドの乳化の容易性の観点からは、メチルジエタノールアミンを有機カルボン酸で中和したものが好ましい。 The compound containing one or more active hydrogen groups and a tertiary ammonium salt is not particularly limited, and examples thereof include alkanolamine. The alkanolamine is not particularly limited, and examples thereof include methylaminoethanol and methyldiethanolamine. By neutralizing these with an organic carboxylic acid such as formic acid or acetic acid, or an inorganic acid such as hydrochloric acid or sulfuric acid to form a salt, the polyurethane can be made water-dispersible. Neutralization can be performed before, during or after the urethanization reaction. Among these, from the viewpoint of easy emulsification of polyimide, those obtained by neutralizing methyldiethanolamine with an organic carboxylic acid are preferable.
　前記、１個以上の活性水素基と第４級アンモニウム塩を有する化合物としては、特に限定されないが、例えば、前記、メチルアミノエタノール、メチルジエタノールアミンなどのアルカノールアミンをジアルキル硫酸により４級化した化合物などがあげられる。前記、ジアルキル硫酸としては、特に限定されないが、例えば、塩化メチル、臭化メチルなどのハロゲン化アルキル、ジメチル硫酸などがあげられる。これらのうち、ポリウレタンの乳化の容易性の観点からは、メチルジエタノールアミンをジメチル硫酸で４級化した化合物が好ましい。 The compound having one or more active hydrogen groups and a quaternary ammonium salt is not particularly limited, and examples thereof include compounds obtained by quaternizing alkanolamines such as methylaminoethanol and methyldiethanolamine with dialkyl sulfuric acid. Can be given. The dialkyl sulfuric acid is not particularly limited, and examples thereof include alkyl halides such as methyl chloride and methyl bromide, dimethyl sulfuric acid, and the like. Among these, from the viewpoint of easy emulsification of polyurethane, a compound obtained by quaternizing methyldiethanolamine with dimethyl sulfate is preferable.
　前記、１個以上の活性水素基とノニオン性親水基を有する化合物としては、特に限定されないが、例えば、ポリオキシエチレングリコール又はポリオキシエチレン－ポリオキシプロピレン共重合体グリコール、ポリオキシエチレン－ポリオキシブチレン共重合体グリコール、ポリオキシエチレン－ポリオキシアルキレン共重合体グリコール又はそのモノアルキルエーテル等のノニオン性基含有化合物又はこれらを共重合して得られるポリエステルポリエーテルポリオールなどがあげられる。これらのうち、エチレンオキシドの繰り返し単位を少なくとも３０質量％以上含有し、数平均分子量３００～２０，０００の化合物が好ましい。 The compound having one or more active hydrogen groups and a nonionic hydrophilic group is not particularly limited. For example, polyoxyethylene glycol or polyoxyethylene-polyoxypropylene copolymer glycol, polyoxyethylene-polyoxy Nonionic group-containing compounds such as butylene copolymer glycol, polyoxyethylene-polyoxyalkylene copolymer glycol, or monoalkyl ethers thereof, or polyester polyether polyols obtained by copolymerizing these compounds. Of these, compounds containing at least 30% by mass of ethylene oxide repeating units and having a number average molecular weight of 300 to 20,000 are preferred.
　（Ｃ）１個以上の活性水素基と親水基を有する化合物としては、これらを１種または２種以上を併用して使用することができる。 (C) As a compound having one or more active hydrogen groups and a hydrophilic group, these can be used alone or in combination of two or more.
　本実施の形態の、（Ｃ）１個以上の活性水素基と親水基を有する化合物の含有量としては、特に限定されないが、ポリイミド水分散体中のポリイミドに対して、３～１５質量％が好ましく、５～１０質量％がより好ましい。これらの範囲であれば、機械強度、機械強度の改善効果の観点から、好ましい。 The content of the compound (C) having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited, but is 3 to 15% by mass with respect to the polyimide in the polyimide aqueous dispersion. Preferably, 5 to 10% by mass is more preferable. If it is these ranges, it is preferable from a viewpoint of the improvement effect of mechanical strength and mechanical strength.
　本実施の形態において、（Ａ）酸無水物、（Ｂ）イソシアネート化合物、および（Ｃ）親水基を有するポリオールを反応する際には、触媒を用いても良い。触媒としては、特に限定されないが、例えば、アミン、四級アンモニウム塩、イミダゾール、アミド、ピリジン、ホスフィン、有機金属塩などがあげられる。機械強度、機械強度の改善効果の観点から、より好ましくはアミン、四級アンモニウム塩であり、四級アンモニウム塩が特に好ましい。具体的にはトリエチルアミン、テトラブチルアンモニウムブロミド等が挙げられる。　また、（Ａ）酸無水物と（Ｂ）イソシアネート化合物を反応させる時に使用することが好ましい。また、触媒の使用量としては、特に限定されないが、酸無水物とイソシアネートの合計重量に対して０．００５～３重量部が好ましく、より好ましくは、０．１～２重量部である。 In this embodiment, a catalyst may be used when (A) an acid anhydride, (B) an isocyanate compound, and (C) a polyol having a hydrophilic group are reacted. The catalyst is not particularly limited, and examples thereof include amines, quaternary ammonium salts, imidazoles, amides, pyridines, phosphines, and organometallic salts. From the viewpoint of mechanical strength and the effect of improving mechanical strength, amines and quaternary ammonium salts are more preferable, and quaternary ammonium salts are particularly preferable. Specific examples include triethylamine and tetrabutylammonium bromide. Moreover, it is preferable to use it when (A) an acid anhydride and (B) an isocyanate compound are reacted. The amount of the catalyst used is not particularly limited, but is preferably 0.005 to 3 parts by weight, more preferably 0.1 to 2 parts by weight with respect to the total weight of the acid anhydride and isocyanate.
　本実施の形態のポリイミド水分散体中のポリイミドの酸価は、１０～１００ｍｇＫＯＨ／ｇであることが好ましく、２０～１００ｍｇＫＯＨ／ｇであることがより好ましく、２０～６０ｍｇＫＯＨ／ｇであることがさらに好ましい。これらの範囲であれば、ポリイミドの乳化安定性が良好であり、機械強度、機械強度の改善効果の観点からも好ましい。本明細書においてポリイミドの酸価は、原料の仕込み量に基づいて、カルボキシル基を有するポリイミド固形分１ｇ中に含まれる遊離カルボキシル基を中和するのに要するＫＯＨのｍｇ数から算出される理論酸価をいう。 The acid value of the polyimide in the polyimide aqueous dispersion of the present embodiment is preferably 10 to 100 mgKOH / g, more preferably 20 to 100 mgKOH / g, and further preferably 20 to 60 mgKOH / g. preferable. If it is these ranges, the emulsion stability of polyimide is favorable and it is preferable also from a viewpoint of the improvement effect of mechanical strength and mechanical strength. In this specification, the acid value of polyimide is calculated from the number of mg of KOH required to neutralize free carboxyl groups contained in 1 g of polyimide solids having carboxyl groups, based on the charged amount of raw materials. Refers to the price.
　本実施の形態のポリイミド水分散体は、（Ａ）酸無水物、（Ｂ）イソシアネート化合物、および（Ｃ）親水基を有するポリオールの反応物に、さらに（Ｄ）ポリオール（ただし（Ｃ）を除く）を反応させることも好ましい形態である。前記（Ｄ）ポリオールとしては、分子内に２個以上の活性水素基を有する化合物であれば、特に限定されない。例えば、分子量４００以下の低分子量ポリオール、ポリエステルポリオール、ポリエーテルポリオール、ひまし油系ポリオール、ポリカーボネートポリオール、又は炭化水素系ポリオール等が挙げられる。これらは、１種または２種以上を組み合わせて用いることができる。これらのうち、成膜性、機械強度、機械強度の改善効果の観点から、ポリエーテルポリオール、ポリカーボネートポリオール、炭化水素系ポリオールが好ましい。 In the polyimide aqueous dispersion of the present embodiment, the reaction product of (A) acid anhydride, (B) isocyanate compound, and (C) polyol having a hydrophilic group is further added to (D) polyol (provided that (C) is excluded). ) Is also a preferred form. The (D) polyol is not particularly limited as long as it is a compound having two or more active hydrogen groups in the molecule. For example, a low molecular weight polyol having a molecular weight of 400 or less, a polyester polyol, a polyether polyol, a castor oil-based polyol, a polycarbonate polyol, or a hydrocarbon-based polyol can be used. These can be used alone or in combination of two or more. Of these, polyether polyols, polycarbonate polyols, and hydrocarbon-based polyols are preferable from the viewpoint of the effect of improving film formability, mechanical strength, and mechanical strength.
　前記低分子量ポリオールは、分子量４００以下のものであれば、特に限定されないが、例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２－プロピレングリコール、１，３－プロピレングリコール、ネオペンチルグリコール、１，３－ブタンジオール、１，４－ブタンジオール、３－メチルペンタンジオール、１，６－ヘキサンジオール、１，８－オクタンジオール、２－メチル－１，３－プロパンジオール、ビスフェノールＡ、水添ビスフェノールＡ、ビスフェノールＦ、シクロヘキサンジメタノール、グリセリン、又はトリメチロールプロパン等が挙げられる。なかでも、トリメチロールプロパンが好ましい。 The low molecular weight polyol is not particularly limited as long as it has a molecular weight of 400 or less. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1 , 3-butanediol, 1,4-butanediol, 3-methylpentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-propanediol, bisphenol A, hydrogenated bisphenol A, bisphenol F, cyclohexane dimethanol, glycerin, trimethylolpropane, etc. are mentioned. Of these, trimethylolpropane is preferable.
　前記ポリエステルポリオールとしては、特に限定されないが、例えば、前記低分子量ポリオールと多価カルボン酸とを反応させてなる水酸基末端エステル化縮合物等が挙げられる。前記多価カルボン酸としては、特に限定されないが、例えば、コハク酸、グルタル酸、アジピン酸、セバシン酸、フタル酸、イソフタル酸、テレフタル酸、トリメリット酸、テトラヒドロフラン酸、エンドメチンテトラヒドロフラン酸、又はヘキサヒドロフタル酸等が挙げられる。これらの中で強度および弾性率の観点から、芳香族環式構造を有するフタル酸、イソフタル酸およびテレフタル酸が好ましい。 The polyester polyol is not particularly limited, and examples thereof include a hydroxyl-terminated esterified condensate obtained by reacting the low molecular weight polyol and a polyvalent carboxylic acid. The polyvalent carboxylic acid is not particularly limited. For example, succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrofuran acid, endomethine tetrahydrofuran acid, or hexa And hydrophthalic acid. Of these, phthalic acid, isophthalic acid and terephthalic acid having an aromatic cyclic structure are preferred from the viewpoint of strength and elastic modulus.
　前記ポリエーテルポリオールとしては、特に限定されないが、例えば、ビスフェノールＡ、ビスフェノールＦなどの前記低分子量ポリオール、ペンタエリスリトール、ソルビトール、又はショ糖などにアルキレンオキサイドを付加重合したもの、ポリテトラメチレンエーテルグリコール等があげられる。前記アルキレンオキサイドとしては、エチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド等が挙げられる。これらの中で強度および弾性率の観点から、芳香族環式構造を有するもの、すなわち、ビスフェノールＡおよびビスフェノールＦにアルキレンオキサイドを付加重合したものが好ましく、ビスフェノールＡにエチレンオキサイドおよび／またはプロピレンオキサイドを付加重合したものがより好ましい。 The polyether polyol is not particularly limited. For example, the low molecular weight polyol such as bisphenol A and bisphenol F, pentaerythritol, sorbitol, sucrose, or the like obtained by addition polymerization of alkylene oxide, polytetramethylene ether glycol, etc. Can be given. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like. Among these, from the viewpoint of strength and elastic modulus, those having an aromatic cyclic structure, that is, those obtained by addition polymerization of alkylene oxide to bisphenol A and bisphenol F are preferred, and ethylene oxide and / or propylene oxide is added to bisphenol A. Those obtained by addition polymerization are more preferred.
　前記ひまし油系ポリオールとしては、特に限定されないが、例えば、ひまし油、ひまし油に水素付加した水添ひまし油、ひまし油脂肪酸又はこれに水素付加した水添ひまし油脂肪酸を用いて製造されたポリオール等が挙げられる。また、ひまし油と他の天然油脂とのエステル交換物、ひまし油と多価アルコールとの反応物、ひまし油脂肪酸と多価アルコールとのエステル化反応物、又はこれらにアルキレンオキサイドを付加重合したポリオール等が挙げられる。 The castor oil-based polyol is not particularly limited, and examples thereof include castor oil, hydrogenated castor oil hydrogenated to castor oil, castor oil fatty acid, or polyol produced using hydrogenated castor oil fatty acid hydrogenated thereto. Also included are transesterification products of castor oil and other natural fats and oils, reaction products of castor oil and polyhydric alcohols, esterification reaction products of castor oil fatty acid and polyhydric alcohols, or polyols obtained by addition polymerization of these with alkylene oxide. It is done.
　前記ポリカーボネートポリオールとしては、特に限定されず、従来公知のものが挙げられる。このようなポリカーボネートポリオールは、例えば、前記低分子量ポリオールとジフェニルカーボネートとの反応により、または、前記低分子量ポリオールとホスゲンとの反応により得られる。 The polycarbonate polyol is not particularly limited, and includes conventionally known polycarbonate polyols. Such a polycarbonate polyol is obtained, for example, by a reaction between the low molecular weight polyol and diphenyl carbonate, or a reaction between the low molecular weight polyol and phosgene.
　前記炭化水素系ポリオールとしては、特に限定されないが、例えば、ポリブタジエンポリオール、ポリイソプレンポリオール、水添ポリブタジエンポリオール、又は水添ポリイソプレンポリオール等が挙げられる。 The hydrocarbon polyol is not particularly limited, and examples thereof include polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, and hydrogenated polyisoprene polyol.
　本実施の形態のポリイミド水分散体は、鎖伸長することも好ましい態様である。前記鎖伸長としては、（Ｅ）アミンを用いて鎖伸長、水中に分散乳化時に系中に存在する水分子により鎖伸長を行うことができる。本実施の形態に用いる（Ｅ）アミンとしては特に限定されないが、例えば、ジアミンやポリアミンなどがあげられる。前記、ジアミンとしては、特に限定されないが、例えば、エチレンジアミン、トリメチレンジアミン、ピペラジン、イソホロンジアミンなどがあげられる。前記、ポリアミンとしては、特に限定されないが、例えば、ジエチレントリアミン、ジプロピレントリアミン、トリエチレンテトラミン、テトラエチレンペンタミン、ペンタエチレンヘキサミンなどがあげられる。これらのうち、エチレンジアミン、ジエチレントリアミンが好ましい。 It is also a preferable aspect that the polyimide aqueous dispersion of the present embodiment is chain-extended. As the chain extension, (E) amine can be used for chain extension, and chain extension can be performed by water molecules present in the system at the time of dispersion emulsification in water. Although it does not specifically limit as (E) amine used for this Embodiment, For example, diamine, a polyamine, etc. are mention | raise | lifted. The diamine is not particularly limited, and examples thereof include ethylene diamine, trimethylene diamine, piperazine, and isophorone diamine. The polyamine is not particularly limited, and examples thereof include diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Of these, ethylenediamine and diethylenetriamine are preferred.
　本実施の形態の（Ｅ）アミンの含有量としては、特に限定されないが、イミドプレポリマーに対して、０．５～２．５質量％が好ましく、０．７～１．５質量％がより好ましい。残存するイソアネート基を（Ｃ）鎖伸長剤を加えて、乳化ミセル中のイソシアシネート基と（Ｃ）鎖伸長剤とを界面重合反応させてウレア結合を生成させる。これにより乳化ミセル内の架橋密度が向上し、三次元架橋構造が形成される。このように三次元架橋構造の形成により、優れた機械強度、機械強度の改善効果が得られる。 The content of the (E) amine in the present embodiment is not particularly limited, but is preferably 0.5 to 2.5% by mass, more preferably 0.7 to 1.5% by mass with respect to the imide prepolymer. preferable. The (C) chain extender is added to the remaining isocyanate groups, and an isocyaninate group and (C) chain extender in the emulsion micelle are subjected to an interfacial polymerization reaction to form a urea bond. Thereby, the crosslinking density in the emulsified micelle is improved, and a three-dimensional crosslinked structure is formed. As described above, the formation of the three-dimensional crosslinked structure can provide excellent mechanical strength and mechanical strength improvement effect.
　本実施の形態のポリイミド水分散体の製造方法としては、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物、必要に応じて（Ｄ）ポリオールを反応させプレポリマーを合成する工程、プレポリマーを水中で乳化する工程を含む。 As a manufacturing method of the polyimide water dispersion of this Embodiment, (A) acid anhydride, (B) polyisocyanate, and (C) the compound which has one or more active hydrogen groups and a hydrophilic group, as needed (D) A step of reacting a polyol to synthesize a prepolymer and a step of emulsifying the prepolymer in water are included.
　本実施の形態のポリイミド水分散体の製造方法としては、プレポリマー中のアニオン性親水基、カチオン性親水基の中和、又は４級化を行ってから、プレポリマーを水中で乳化する工程を行うことも好ましい。 As a method for producing the polyimide aqueous dispersion of the present embodiment, the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. It is also preferable to do this.
　本実施の形態のポリイミド水分散体の製造方法としては、機械強度、機械強度の改善効果の観点から、プレポリマーを水中で乳化分散した後、鎖伸長する工程を含むことも好ましい。 The method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water, from the viewpoint of improving the mechanical strength and mechanical strength.
　本実施の形態のポリイミド水分散体の製造方法としては、特に限定されないが、必要に応じて溶剤の存在下、プレポリマーを合成する工程、鎖伸長工程を行なうことができる。前記溶剤としては、イソシアネート基と不活性で、かつ、生成するポリイミドを溶解し得る溶剤であれば特に限定されない。これらの溶剤としては、特に限定されないが、例えば、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）、Ｎ－メチル－２－ピロリドンなどがあげられる。反応で使用したこれら親水性有機溶剤は、最終的には除去するのが好ましい。 The method for producing the polyimide aqueous dispersion of the present embodiment is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent. The solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide. These solvents are not particularly limited, and examples thereof include N, N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
　本実施の形態のポリイミド水分散体を製造の際には架橋剤を使用することもできる。架橋剤としては、特に限定されないが、アジリジン、オキサゾリン、カルボジイミド、変性ポリイソシアネート、ポリエポキシド化合物などがあげられる。これらの架橋剤は１種または２種以上を併用して使用することができる。 In the production of the polyimide aqueous dispersion of the present embodiment, a crosslinking agent can be used. The crosslinking agent is not particularly limited, and examples thereof include aziridine, oxazoline, carbodiimide, modified polyisocyanate, and polyepoxide compound. These crosslinking agents can be used alone or in combination of two or more.
　また、本実施の形態のポリイミド水分散体には、触媒、酸化防止剤、吸湿剤、防黴剤、シランカップリング剤など、必要に応じて各種の添加剤を添加することができる。シランカップリング剤としては、例えばアルコキシシラン類、ビニル基含有シランカップリング剤、エポキシ基含有シランカップリング剤、メタクリル基含有シランカップリング剤、アクリル基含有シランカップリング剤などが挙げられる。 In addition, various additives such as a catalyst, an antioxidant, a hygroscopic agent, an antifungal agent, and a silane coupling agent can be added to the polyimide aqueous dispersion of the present embodiment as necessary. Examples of the silane coupling agent include alkoxysilanes, vinyl group-containing silane coupling agents, epoxy group-containing silane coupling agents, methacryl group-containing silane coupling agents, and acrylic group-containing silane coupling agents.
　本実施の形態のポリイミド水分散体の貯蔵安定性としては、特に限定されないが、実施例に記載の方法において、分離、沈殿が見られないことが好ましい。 The storage stability of the polyimide aqueous dispersion of the present embodiment is not particularly limited, but it is preferable that separation and precipitation are not observed in the methods described in the examples.
　本実施の形態のポリイミド水分散体の機械強度の改善効果としては、特に限定されないが、実施例に記載の方法において、１００％、２００％、３００％およびモジュラス改善効果が１０５％以上であることが好ましく、１２０％以上であることがより好ましい。 The effect of improving the mechanical strength of the polyimide aqueous dispersion of the present embodiment is not particularly limited, but in the method described in the examples, 100%, 200%, 300%, and the modulus improving effect is 105% or more. Is more preferable, and 120% or more is more preferable.
　本実施の形態のポリイミド水分散体から得られる皮膜の皮膜強度、１００％モジュラス、ヤング率、伸度としては、特に限定されないが、実施例に記載の方法において、それぞれ５（Ｎ／ｍｍ２）、４（Ｎ／ｍｍ２）、４（Ｎ／ｍｍ２）、３０％以上であることが好ましい。 The film strength, 100% modulus, Young's modulus, and elongation of the film obtained from the polyimide aqueous dispersion of the present embodiment are not particularly limited, but in the methods described in the examples, 5 (N / mm 2 ) respectively. 4 (N / mm 2 ), 4 (N / mm 2 ), and preferably 30% or more.
　［第1の実施の形態に係る実施例］
　以下、実施例及び比較例に基づいて、第1の実施の形態について詳細に説明する。本発明の技術的範囲はこれらの実施例に限定されるものではない。なお、本明細書中に於ける「部」、「％」は、特に明示した場合を除き、「質量部」、「質量％」をそれぞれ表している。 [Example according to the first embodiment]
Hereinafter, the first embodiment will be described in detail based on examples and comparative examples. The technical scope of the present invention is not limited to these examples. In the present specification, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified.
　＜実施例１＞
　撹拌機、還流冷却管、温度計および窒素吹き込み管を備えた４つ口フラスコにピロメリット酸二無水物（ＰＭＤＡ(ダイセル社製)）１０．２重量部、イソホロンジイソシアネート（ＩＰＤＩ）３１．１重量部、テトラブチルアンモニウムブロミド０．５重量部、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）３８．０重量部と加え、１２０℃で２時間反応させた後、ＤＭＡｃ２３．８重量部、ジメチロールプロピオン酸（ＢｉｓＭＰＡ）６．２重量部と加えて７５℃で２時間反応させた。この溶液にポリブタジエンポリオール（Ｋｒａｓｏｌ　ＬＢＨ－Ｐ２０００）５２．５重量部、メチルエチルケトン（ＭＥＫ）５０．０重量部、トリエチルアミン４．８重量部と加えてさらに７５℃で３時間反応させた後、ＭＥＫ２０．０重量部を加えて希釈し、ウレタンイミドプレポリマー溶液（Ａ）を得た。この溶液の不揮発分に対する遊離のイソシアネート基含有量は１．９１％であった。 <Example 1>
A four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube is equipped with 10.2 parts by weight of pyromellitic dianhydride (PMDA (manufactured by Daicel)) and 31.1 parts by weight of isophorone diisocyanate (IPDI). Parts, 0.5 parts by weight of tetrabutylammonium bromide and 38.0 parts by weight of N, N-dimethylacetamide (DMAc) and reacted at 120 ° C. for 2 hours, then 23.8 parts by weight of DMAc, dimethylolpropionic acid ( BisMPA) 6.2 parts by weight was added and reacted at 75 ° C. for 2 hours. To this solution was added 52.5 parts by weight of polybutadiene polyol (Krasol LBH-P2000), 50.0 parts by weight of methyl ethyl ketone (MEK), and 4.8 parts by weight of triethylamine, and the mixture was further reacted at 75 ° C. for 3 hours. A part by weight was added for dilution to obtain a urethane imide prepolymer solution (A). The free isocyanate group content with respect to the nonvolatile content of this solution was 1.91%.
　Ａに対し、水１６６．８重量部を加えてホモミキサーを用いて乳化し、続いて、ジエチレントリアミン０．８重量部を加えて鎖伸長反応を３０℃で１時間行った。かかる反応後、ＭＥＫを減圧留去して、水中にポリウレタンイミド樹脂が乳化されてなるポリイミド水分散体（不揮発分：３１．６％、ｐＨ：７．９、粘度：６０１ｍＰａｓ、粒子径：０．０６μｍ）を作製した。 A 166.8 parts by weight of water was added to A and emulsified using a homomixer, and then 0.8 parts by weight of diethylenetriamine was added to carry out a chain extension reaction at 30 ° C. for 1 hour. After this reaction, MEK was distilled off under reduced pressure, and a polyimide aqueous dispersion obtained by emulsifying polyurethaneimide resin in water (nonvolatile content: 31.6%, pH: 7.9, viscosity: 601 mPas, particle size: 0.00). 06 μm).
　＜実施例２～１０＞
　表１記載の処方に変更した以外は、実施例１と同様の方法により、合成を行った。 <Examples 2 to 10>
The synthesis was performed in the same manner as in Example 1 except that the formulation shown in Table 1 was changed.
　用いた化合物の略称を以下に示す。
ＰＭＤＡ：無水ピロメリット酸二無水物 (ダイセル製)
ＢＴＤＡ：ベンゾフェノンテトラカルボン酸二無水物 (ダイセル製)
ＢｉｓＭＰＡ：ジメチロールプロピオン酸
ＬＢＨ－Ｐ２０００：Ｋｒａｓｏｌ　ＬＢＨ－Ｐ２０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状ポリブタジエン）
ＬＢＨ－Ｐ３０００：Ｋｒａｓｏｌ　ＬＢＨ－Ｐ３０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状ポリブタジエン）
ＨＢＨ－Ｐ２０００：Ｋｒａｓｏｌ　ＨＬＢＨ－Ｐ２０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状水素添加ポリブタジエン）
ＰＴＭＧ－２０００：（三菱化学製、ポリテトラメチレンエーテルグリコール）
Ｒ－１５ＨＴ：Ｐｏｌｙｂｄ　Ｒ－１５ＨＴ（出光興産社製、末端水酸基変性液状ポリブタジエン)
ＰＣＤＬ　Ｔ－６００２：デュラノールＰＣＤＬ　Ｔ－６００２（旭化成ケミカルズ製、ポリカーボネートジオール)
ＩＰＤＩ：イソホロンジイソシアネート Abbreviated names of the compounds used are shown below.
PMDA: pyromellitic dianhydride (Daicel)
BTDA: Benzophenone tetracarboxylic dianhydride (Daicel)
BisMPA: dimethylolpropionic acid LBH-P2000: Krasol LBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
LBH-P3000: Krasol LBH-P3000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
HBH-P2000: Krasol HLBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid hydrogenated polybutadiene)
PTMG-2000: (Mitsubishi Chemical, polytetramethylene ether glycol)
R-15HT: Polybd R-15HT (manufactured by Idemitsu Kosan Co., Ltd., terminal hydroxyl group-modified liquid polybutadiene)
PCDL T-6002: Duranol PCDL T-6002 (Asahi Kasei Chemicals, polycarbonate diol)
IPDI: Isophorone diisocyanate
　＜比較例１～３＞
（比較例１）
　撹拌機、還流冷却管、温度計および窒素吹き込み管を備えた４つ口フラスコにイソホロンジアミン４４．６重量部、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）６１８．２重量部、ピロメリット酸二無水物５５．４重量部と加え、５０℃で３時間反応させてポリアミック酸溶液を得た。この溶液を１８０℃で1時間加熱してイミド化を実施した。赤外吸収スペクトルにて１７８０ｃｍ－１、１３４０ｃｍ－１にイミド構造由来の吸収が出現したことから反応の進行を確認した。しかし、この生成物は溶剤不溶であり、以降のウレタン化反応に用いることはできなかった。
（比較例２）
　撹拌機、還流冷却管、温度計および窒素吹き込み管を備えた４つ口フラスコにイソホロンジアミン６１．０重量部、N,N-ジメチルアセトアミド（ＤＭＡｃ）９９．２重量部、ピロメリット酸二無水物３９．０重量部と加えたが、すぐに白色の不溶物が生成し、ポリアミック酸溶液を得ることはできなかった。
（比較例３）
　撹拌機、還流冷却管、温度計および窒素吹き込み管を備えた４つ口フラスコにポリブタジエンポリオール （Ｋｒａｓｏｌ　ＬＢＨ－Ｐ２０００）２９２．１重量部、イソホロ
ンジイソシアネート１２３．４重量部、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）２００．０重量部と加え、７５℃で２時間反応させた後、ＤＭＡｃ２５０．０重量部、ジメチロールプロピオン酸３７．２重量部と加えて７５℃で４時間反応させた。この溶液にイソホロンジアミン４８．２重量部、ＤＭＡｃ５０．０重量部と加えてさらに室温で３０分反応させた後、この溶液の不揮発分に対する遊離のイソシアネート基含有量が０％となったことを確認した。続いてこの溶液をＤＭＡｃ３０６．１重量部を加えて希釈し、ピロメリット酸二無水物 １０．１重量部を加えて室温で一晩反応させてウレタンアミック酸溶液（Ａ）を得た。さらにトリエチルアミンを２８．１重量部加えた後、撹拌しながら水を添加したところ、沈殿を生じて乳化は不可能であった。また、（Ａ）を180 ℃で１時間加熱したところ、生成物のＩＲスペクトルにおいてイミド構造由来の吸収は見られなかった。 <Comparative Examples 1 to 3>
(Comparative Example 1)
44.6 parts by weight of isophoronediamine, 618.2 parts by weight of N, N-dimethylacetamide (DMAc), pyromellitic dianhydride in a four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube It was added with 55.4 parts by weight and reacted at 50 ° C. for 3 hours to obtain a polyamic acid solution. This solution was heated at 180 ° C. for 1 hour to perform imidization. Infrared absorption spectrum at 1780 cm -1, the absorption derived from the imide structure 1340 cm -1 was confirmed the progress of the reaction since it has appeared. However, this product was insoluble in a solvent and could not be used for the subsequent urethanization reaction.
(Comparative Example 2)
In a four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube, 61.0 parts by weight of isophoronediamine, 99.2 parts by weight of N, N-dimethylacetamide (DMAc), pyromellitic dianhydride Although 39.0 parts by weight were added, a white insoluble material was immediately formed, and a polyamic acid solution could not be obtained.
(Comparative Example 3)
A four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blowing tube was charged with 292.1 parts by weight of polybutadiene polyol (Krasol LBH-P2000), 123.4 parts by weight of isophorone diisocyanate, N, N-dimethylacetamide ( DMAc) 200.0 parts by weight was added and reacted at 75 ° C. for 2 hours, and then DMAc 250.0 parts by weight and dimethylolpropionic acid 37.2 parts by weight were added and reacted at 75 ° C. for 4 hours. After adding 48.2 parts by weight of isophoronediamine and 50.0 parts by weight of DMAc to this solution and further reacting at room temperature for 30 minutes, it was confirmed that the content of free isocyanate groups with respect to the nonvolatile content of this solution was 0%. did. Subsequently, this solution was diluted with 306.1 parts by weight of DMAc, and 10.1 parts by weight of pyromellitic dianhydride was added and reacted at room temperature overnight to obtain a urethane amic acid solution (A). Further, 28.1 parts by weight of triethylamine was added and then water was added with stirring. As a result, precipitation occurred and emulsification was impossible. When (A) was heated at 180 ° C. for 1 hour, no absorption derived from the imide structure was observed in the IR spectrum of the product.
　＜評価方法＞
（貯蔵安定性）
　得られたポリイミド水分散体を４０℃の恒温槽に保管し、１ヶ月後の変化を目視にて確認した。
○：分離および沈殿がみられない。
×：分離または沈殿がみられる。
（皮膜、評価サンプルの調製方法）
　機械強度の改善効果および皮膜強度、１００％モジュラス、ヤング率、伸度測定に使用する皮膜は下記方法で調製した。 <Evaluation method>
(Storage stability)
The obtained polyimide aqueous dispersion was stored in a constant temperature bath at 40 ° C., and the change after one month was visually confirmed.
○: Separation and precipitation are not observed.
X: Separation or precipitation is observed.
(Method for preparing film and evaluation sample)
The effect of improving mechanical strength and film strength, 100% modulus, Young's modulus, and film used for measuring elongation were prepared by the following methods.
　水分散体を、膜厚５００μｍとなるようにテフロン（登録商標）コーティングシャーレに投入し、８０℃で６時間、１２０℃で３０分、１５０℃で１時間乾燥し、皮膜を作製した。
　上記皮膜をダンベル状試験片(３号)の大きさに切断することにより評価サンプルを作製した。
（機械強度の改善効果）
　水系ウレタン樹脂（スーパーフレックス４７０、第一工業製薬社製）／得られたポリイミド水分散体＝８５／１５（重量比）で混合した水分散体を使用した。
　ＪＩＳ－Ｋ－６３０１に準じて、引張速度１００ｍｍ／ｍｉｎで引張強度（Ｎ／ｍｍ２）、伸度（％）、１００％（Ｎ／ｍｍ２）モジュラスおよびを測定した。なお、評価はスーパーフレックス４７０で作成した皮膜の測定結果を１００としたときの指数として表した。すなわち、実施例１の場合、（実施例１の実測値）／（スーパーフレックス４７０で作成した皮膜の測定結果）×１００として算出した。
（皮膜強度、１００％モジュラス、ヤング率、伸度）
　得られたポリイミド水分散体のみを使用し、皮膜を作成した。ＪＩＳ－Ｋ－６３０１に準じて測定した。 The aqueous dispersion was put into a Teflon (registered trademark) coating petri dish so as to have a film thickness of 500 μm, and dried at 80 ° C. for 6 hours, 120 ° C. for 30 minutes, and 150 ° C. for 1 hour to prepare a film.
An evaluation sample was prepared by cutting the film into the size of a dumbbell-shaped test piece (No. 3).
(Mechanical strength improvement effect)
An aqueous dispersion mixed with an aqueous urethane resin (Superflex 470, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) / Obtained polyimide aqueous dispersion = 85/15 (weight ratio) was used.
In accordance with JIS-K-6301, tensile strength (N / mm 2 ), elongation (%), 100% (N / mm 2 ) modulus and the like were measured at a tensile speed of 100 mm / min. The evaluation was expressed as an index when the measurement result of the film prepared with Superflex 470 was taken as 100. That is, in the case of Example 1, it was calculated as (actual value of Example 1) / (measurement result of the film created by Superflex 470) × 100.
(Coating strength, 100% modulus, Young's modulus, elongation)
Using only the obtained polyimide aqueous dispersion, a film was prepared. The measurement was performed according to JIS-K-6301.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　＜評価結果＞
　実施例１～１０から分かるように、本実施の形態のポリイミド水分散体は、貯蔵安定性、機械強度の改善効果、得られる皮膜の機械強度が良好であることが分かる。 <Evaluation results>
As can be seen from Examples 1 to 10, it can be seen that the polyimide aqueous dispersion of the present embodiment has good storage stability, mechanical strength improvement effect, and good mechanical strength of the resulting film.
　一方、比較例１のようにアミン末端ポリイミドを合成し、NCO基末端ウレタンプレポリマーと反応させる方法では、ポリイミドが溶剤不溶となり、ウレタンプレポリマーとの反応に至らず、ポリイミド水分散体を得られなかった。比較例２のような設計では、ポリイミドの前駆体を得ることができなかった。比較例３のように、アミン末端ウレタンプレポリマーと酸無水物を反応させる方法では、生成物においてイミド化が見られず、乳化も不可能であり、ポリイミド水分散体を得られなかった。 On the other hand, in the method of synthesizing an amine-terminated polyimide as in Comparative Example 1 and reacting with an NCO group-terminated urethane prepolymer, the polyimide becomes solvent insoluble and does not lead to a reaction with the urethane prepolymer, and a polyimide aqueous dispersion can be obtained. There wasn't. In the design as in Comparative Example 2, a polyimide precursor could not be obtained. As in Comparative Example 3, in the method of reacting the amine-terminated urethane prepolymer and the acid anhydride, imidization was not observed in the product, emulsification was impossible, and a polyimide aqueous dispersion could not be obtained.
［第２の実施の形態］
　次に、本発明の第２の実施の形態のポリイミド水分散体について説明する。以下に説明する内容以外については、本発明の第１の実施の形態と同様である。 [Second Embodiment]
Next, the polyimide water dispersion according to the second embodiment of the present invention will be described. The contents other than those described below are the same as those in the first embodiment of the present invention.
　第２の実施の形態に係るポリイミド水分散体は、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応して得られるポリイミド水分散体であって、酸価が５０ｍｇＫＯＨ／ｇ以下である。 The polyimide aqueous dispersion according to the second embodiment is obtained by reacting (A) acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group. A polyimide aqueous dispersion having an acid value of 50 mgKOH / g or less.
　このような特徴により、本実施の形態のポリイミド水分散体は、水分散体であることから環境適合性が高く、使用設備を防爆構造等にする必要もない。また、電極用結着剤としての性能も有する。 Due to such characteristics, the polyimide aqueous dispersion of the present embodiment is an aqueous dispersion and thus has high environmental compatibility, and it is not necessary to use an explosion-proof structure for the equipment used. It also has performance as a binder for electrodes.
　＜（Ａ）酸無水物＞
　本実施の形態の（Ａ）酸無水物としては、カルボン酸無水物をいい、２分子のカルボン酸を脱水縮合させた化合物であれば特に限定されるものではない。たとえば、第1の実施
の形態において例示した化合物のうち、耐電解液性、結着性の観点から、ＰＭＤＡ、ＢＴＤＡが好ましい。 <(A) Acid anhydride>
The (A) acid anhydride of the present embodiment is a carboxylic acid anhydride and is not particularly limited as long as it is a compound obtained by dehydration condensation of two molecules of carboxylic acid. For example, among the compounds exemplified in the first embodiment, PMDA and BTDA are preferable from the viewpoints of resistance to electrolytic solution and binding.
　＜（Ｂ）ポリイソシアネート＞
　本実施の形態の（Ｂ）ポリイソシアネートとしては、本技術分野で一般的に使用されるポリイソシアネートであれば特に限定されるものではない。たとえば、第1の実施の形態において例示した化合物のうち、耐電解液性、結着性の観点から、脂環族ポリイソシアネートが好ましく、イソホロンジイソシアネートがより好ましい。 <(B) Polyisocyanate>
The polyisocyanate (B) of the present embodiment is not particularly limited as long as it is a polyisocyanate generally used in this technical field. For example, among the compounds exemplified in the first embodiment, an alicyclic polyisocyanate is preferable and isophorone diisocyanate is more preferable from the viewpoint of electrolytic solution resistance and binding properties.
　本実施の形態において、（Ａ）酸無水物と（Ｂ）イソシアネート化合物の混合割合は、特に限定されないが、例えば、モル比で、（Ａ）／（Ｂ）＝１００／１０３～１００／５００が好ましく、より好ましくは（Ａ）／（Ｂ）＝１００／１５０～１００／３００である。これらの範囲であれば、耐電解液性、結着性が良好である。 In the present embodiment, the mixing ratio of (A) acid anhydride and (B) isocyanate compound is not particularly limited. For example, (A) / (B) = 100/103 to 100/500 in terms of molar ratio. Preferably, (A) / (B) = 100/150 to 100/300. Within these ranges, the electrolytic solution resistance and the binding property are good.
　＜（Ｃ）１個以上の活性水素基と親水基を有する化合物＞
　本実施の形態の（Ｃ）１個以上の活性水素基と親水基を有する化合物としては、１個以上の活性水素基と親水性基を有する化合物であれば特に限定されない。たとえば、第1の実施の形態で例示した化合物であればよい。なお、（Ｃ）１個以上の活性水素基と親水基を有する化合物は、２，６－ジオキシ安息香酸であってもよい。 <(C) Compound having one or more active hydrogen groups and hydrophilic group>
(C) The compound having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited as long as it is a compound having one or more active hydrogen groups and a hydrophilic group. For example, it may be a compound exemplified in the first embodiment. Note that (C) the compound having one or more active hydrogen groups and a hydrophilic group may be 2,6-dioxybenzoic acid.
　本実施の形態の、（Ｃ）１個以上の活性水素基と親水基を有する化合物の含有量としては、特に限定されないが、ポリイミド水分散体中のポリイミドに対して、３～１５質量％が好ましく、５～１０質量％がより好ましい。これらの範囲であれば、ポリイミドの乳化安定性が良好であり、かつ耐電解液性が良好である。 The content of the compound (C) having one or more active hydrogen groups and a hydrophilic group in the present embodiment is not particularly limited, but is 3 to 15% by mass with respect to the polyimide in the polyimide aqueous dispersion. Preferably, 5 to 10% by mass is more preferable. If it is these ranges, the emulsion stability of a polyimide is favorable and electrolyte solution resistance is favorable.
　本実施の形態のポリイミド水分散体中のポリイミドの酸価は、５０ｍｇＫＯＨ／ｇ以下である。５～４５ｍｇＫＯＨ／ｇであることが好ましく、１０～４０ｍｇＫＯＨ／ｇであることがより好ましい。これらの範囲であれば、ポリイミドの乳化安定性が良好であり、かつ耐電解液性、結着性の観点からも好ましい。本明細書においてポリイミドの酸価は、原料の仕込み量に基づいて、カルボキシル基を有するポリイミド固形分１ｇ中に含まれる遊離カルボキシル基を中和するのに要するＫＯＨのｍｇ数から算出される理論酸価をいう。 The acid value of the polyimide in the polyimide aqueous dispersion of the present embodiment is 50 mgKOH / g or less. 5 to 45 mgKOH / g is preferable, and 10 to 40 mgKOH / g is more preferable. If it is these ranges, the emulsification stability of a polyimide is favorable, and it is preferable also from a viewpoint of electrolyte solution resistance and binding property. In this specification, the acid value of polyimide is calculated from the number of mg of KOH required to neutralize free carboxyl groups contained in 1 g of polyimide solids having carboxyl groups, based on the charged amount of raw materials. Refers to the price.
　本実施の形態のポリイミド水分散体は、（Ａ）酸無水物、（Ｂ）イソシアネート化合物、および（Ｃ）親水基を有するポリオールの反応物に、さらに（Ｄ）ポリオール（ただし（Ｃ）を除く）を反応させることも好ましい形態である。前記（Ｄ）ポリオールとしては、分子内に２個以上の活性水素基を有する化合物であれば、特に限定されない。例えば、分子量４００以下の低分子量ポリオール、ポリエステルポリオール、ポリエーテルポリオール、ひまし油系ポリオール、ポリカーボネートポリオール、又は炭化水素系ポリオール等が挙げられる。これらは、１種または２種以上を組み合わせて用いることができる。これらのうち、耐電解液性、結着性の観点から、ポリエーテルポリオール、炭化水素系ポリオールが好ましい。 In the polyimide aqueous dispersion of the present embodiment, the reaction product of (A) acid anhydride, (B) isocyanate compound, and (C) polyol having a hydrophilic group is further added to (D) polyol (provided that (C) is excluded). ) Is also a preferred form. The (D) polyol is not particularly limited as long as it is a compound having two or more active hydrogen groups in the molecule. For example, a low molecular weight polyol having a molecular weight of 400 or less, a polyester polyol, a polyether polyol, a castor oil-based polyol, a polycarbonate polyol, or a hydrocarbon-based polyol can be used. These can be used alone or in combination of two or more. Of these, polyether polyols and hydrocarbon polyols are preferable from the viewpoint of resistance to electrolytic solution and binding properties.
　本実施の形態のポリイミド水分散体は、鎖伸長することも好ましい態様である。前記鎖伸長としては、（Ｅ）アミンを用いて鎖伸長、水中に分散乳化時に系中に存在する水分子により鎖伸長を行うことができる。これらのうち、耐電解液性、結着性の観点から、アミン伸長が好ましい。本実施の形態に用いる（Ｅ）アミンとしては特に限定されないが、例えば、第1の実施の形態で例示したジアミンやポリアミンなどがあげられる。これらのうち、エチレンジアミン、ジエチレントリアミンが好ましい。 It is also a preferable aspect that the polyimide aqueous dispersion of the present embodiment is chain-extended. As the chain extension, (E) amine can be used for chain extension, and chain extension can be performed by water molecules present in the system at the time of dispersion emulsification in water. Of these, amine elongation is preferable from the viewpoint of resistance to electrolytic solution and binding. The (E) amine used in the present embodiment is not particularly limited, and examples thereof include diamines and polyamines exemplified in the first embodiment. Of these, ethylenediamine and diethylenetriamine are preferred.
　本実施の形態の（Ｅ）アミンの含有量としては、特に限定されないが、イミドプレポリマーに対して、０．５～２．５質量％が好ましく、０．７～１．５質量％の範囲であれば耐電解液性、結着性が特に優れたものとなる。残存するイソアネート基を（Ｃ）鎖伸長剤を加えて、乳化ミセル中のイソシアシネート基と（Ｃ）鎖伸長剤とを界面重合反応させてウレア結合を生成させる。これにより乳化ミセル内の架橋密度が向上し、三次元架橋構造が形成される。このように三次元架橋構造の形成により、優れた耐電解液性、結着性が得られる。 The content of (E) amine in the present embodiment is not particularly limited, but is preferably 0.5 to 2.5% by mass, and 0.7 to 1.5% by mass with respect to the imide prepolymer. If so, the electrolytic solution resistance and the binding property are particularly excellent. The (C) chain extender is added to the remaining isocyanate groups, and an isocyaninate group and (C) chain extender in the emulsion micelle are subjected to an interfacial polymerization reaction to form a urea bond. Thereby, the crosslinking density in the emulsified micelle is improved, and a three-dimensional crosslinked structure is formed. Thus, by forming a three-dimensional crosslinked structure, excellent electrolytic solution resistance and binding properties can be obtained.
　本発明のポリイミド水分散体の製造方法としては、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物、必要に応じて（Ｄ）ポリオールを反応させプレポリマーを合成する工程、プレポリマーを水中で乳化する工程を含む。 As the method for producing the polyimide aqueous dispersion of the present invention, (A) acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group, if necessary (D ) A step of reacting a polyol to synthesize a prepolymer and a step of emulsifying the prepolymer in water.
　本発明のポリイミド水分散体の製造方法としては、プレポリマー中のアニオン性親水基、カチオン性親水基の中和、又は４級化を行ってから、プレポリマーを水中で乳化する工程を行うことも好ましい。 As the method for producing the polyimide aqueous dispersion of the present invention, the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. Is also preferable.
　本実施の形態のポリイミド水分散体の製造方法としては、生成物の耐電解液性、結着性の観点から、プレポリマーを水中で乳化分散した後、鎖伸長する工程を含むことも好ましい。 The method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water from the viewpoint of the electrolytic solution resistance and binding properties of the product.
　本発明のポリイミド水分散体の製造方法としては、特に限定されないが、必要に応じて溶剤の存在下、プレポリマーを合成する工程、鎖伸長工程を行なうことができる。前記溶剤としては、イソシアネート基と不活性で、かつ、生成するポリイミドを溶解し得る溶剤であれば特に限定されない。これらの溶剤としては、特に限定されないが、例えば、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）、Ｎ－メチル－２－ピロリドンなどがあげられる。反応で使用したこれら親水性有機溶剤は、最終的には除去するのが好ましい。 The production method of the polyimide aqueous dispersion of the present invention is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent. The solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide. These solvents are not particularly limited, and examples thereof include N, N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
　本実施の形態のポリイミド水分散体は、得られる皮膜の耐電解液性、結着性が良好であることから、リチウム二次電池の電極用結着剤として用いることができる。結着剤としては、本実施の形態のポリイミド水分散体を単独で使用することもでき、他の結着剤を併用することもできる。前記他の結着剤としては、特に限定されないが、ポリフッ化ビニリデン、ポリフッ化ビニリデン共重合体樹脂、フッ素系樹脂、スチレン－ブタジエンゴム、エチレン－プロピレンゴム、スチレン－アクリロニトリル共重合体、アクリル共重合体、およびウレタン樹脂（ただし（Ｘ）を除く）の水分散体、からなる群より選ばれる１種以上（Ｙ）が好ましい。これらのうち、スチレン－ブタジエンゴム、ウレタン樹脂の水分散体が好ましい。 The polyimide aqueous dispersion of the present embodiment can be used as a binder for an electrode of a lithium secondary battery because the resulting film has good electrolytic solution resistance and binding properties. As a binder, the polyimide water dispersion of this Embodiment can also be used independently, and another binder can also be used together. The other binder is not particularly limited, but polyvinylidene fluoride, polyvinylidene fluoride copolymer resin, fluorine resin, styrene-butadiene rubber, ethylene-propylene rubber, styrene-acrylonitrile copolymer, acrylic copolymer. One or more (Y) selected from the group consisting of a coalescence and an aqueous dispersion of urethane resin (excluding (X)) is preferred. Of these, aqueous dispersions of styrene-butadiene rubber and urethane resin are preferred.
　本実施の形態のリチウム二次電池の電極用結着剤は、電極に用いることもできる。本実施の形態の結着剤は正極と負極のどちらにでも利用可能である。本実施の形態の電極は、電極用結着剤を使用したものであれば特に限定されないが、電極活物質、導電剤、及び電極活物質並びに導電剤を集電体に結着させる結着剤等から構成される。 The electrode binder for the lithium secondary battery of this embodiment can also be used for an electrode. The binder of this embodiment can be used for both the positive electrode and the negative electrode. The electrode of the present embodiment is not particularly limited as long as it uses an electrode binder, but the electrode active material, the conductive agent, the electrode active material, and the binder that binds the conductive agent to the current collector. Etc.
　本実施の形態のリチウム二次電池の正極に使用する正極活物質としては、リチウムイオンの挿入、脱離が可能であるものであれば、特に制限されることはない。例えば、ＣｕＯ、Ｃｕ２Ｏ、ＭｎＯ２、ＭｏＯ３、Ｖ２Ｏ５、ＣｒＯ３、ＭｏＯ３、Ｆｅ２Ｏ３、Ｎｉ２Ｏ３、ＣｏＯ３等の金属酸化物、ＬｉｘＣｏＯ２、ＬｉｘＮｉＯ２、ＬｉｘＭｎ２Ｏ４、ＬｉＦｅＰＯ４などのリチウムと遷移金属との複合酸化物や、ＴｉＳ２、ＭｏＳ２、ＮｂＳｅ３などの金属カルコゲン化物、ポリアセン、ポリパラフェニレン、ポリピロール、ポリアニリン等の導電性高分子化合物等が挙げられる。上記の中でも、一般に高電圧系と呼ばれる、コバルト、ニッケル、マンガン等の遷移金属から選ばれる１種以上とリチウムとの複合酸化物が、リチウムイオンの放出性や、高電圧が得られやすい点で好ましい。コバルト、ニッケル、マンガンとリチウムとの複合酸化物の具体例としては、ＬｉＣｏＯ２、ＬｉＭｎＯ２、ＬｉＭｎ２Ｏ４、ＬｉＮｉＯ２、ＬｉＮｉｘＣｏ（１－ｘ）Ｏ２、ＬｉＭｎａＮｉｂＣｏｃ（ａ＋ｂ＋ｃ＝１）などがあげられる。また、これらのリチウム複合酸化物に、少量のフッ素、ホウ素、アルミニウム、クロム、ジルコニウム、モリブデン、鉄などの元素をドーブしたものや、リチウム複合酸化物の粒子表面を、炭素、ＭｇＯ、Ａｌ２Ｏ３、ＳｉＯ２などで表面処理したものも使用できる。これらのうち、ＬｉＦｅＰＯ４、ＬｉＭｎ２Ｏ４、ＬｉＮｉｘＣｏ（１－ｘ）Ｏ２が好ましい。上記正極活物質は２種類以上を併用することも可能である。 The positive electrode active material used for the positive electrode of the lithium secondary battery of this embodiment is not particularly limited as long as it can insert and desorb lithium ions. For example, CuO, Cu 2 O, MnO 2 , MoO 3 , V 2 O 5 , CrO 3 , MoO 3 , Fe 2 O 3, Ni 2 O 3, CoO 3 and other metal oxides, LixCoO 2 , LixNiO 2 , LixMn 2 O 4 , composite oxides of lithium and transition metals such as LiFePO 4 , metal chalcogenides such as TiS 2 , MoS 2 , and NbSe 3 , conductive polymer compounds such as polyacene, polyparaphenylene, polypyrrole, and polyaniline It is done. Among the above, a composite oxide of lithium and at least one selected from transition metals such as cobalt, nickel and manganese, which is generally called a high voltage system, is capable of obtaining lithium ion release properties and high voltage. preferable. Specific examples of the composite oxide of cobalt, nickel, manganese and lithium include LiCoO 2 , LiMnO 2 , LiMn 2 O 4 , LiNiO 2 , LiNixCo (1-x) O 2 , LiMnaNibCoc (a + b + c = 1) and the like. It is done. In addition, these lithium composite oxides doped with a small amount of elements such as fluorine, boron, aluminum, chromium, zirconium, molybdenum, iron, etc., or the surface of lithium composite oxide particles are made of carbon, MgO, Al 2 O 3 , those treated with SiO 2 or the like can also be used. Of these, LiFePO 4 , LiMn 2 O 4 , and LiNixCo (1-x) O 2 are preferable. Two or more kinds of the positive electrode active materials can be used in combination.
　本実施の形態のリチウム二次電池の負極に使用する負極活物質としては、金属リチウム又はリチウムイオンの挿入、脱離が可能であるものであれば、特に制限されることはない。例えば、炭素材料、金属材料、リチウム遷移金属窒化物、結晶性金属酸化物、非晶質金属酸化物、ケイ素化合物、導電性ポリマーなどがあげられる。前記、炭素材料としては、特に限定されないが、例えば、天然黒鉛、人造黒鉛、難黒鉛化炭素、易黒鉛化炭素などがあげられる。前記、金属材料としては、特に限定されないが、例えば、金属リチウムや合金、スズ化合物などがあげられる。具体例としては、Ｌｉ４Ｔｉ５Ｏ１２、ＮｉＳｉ５Ｃ６などがあげられる。これらのうち、天然黒鉛、ＳｉＯ、Ｌｉ４Ｔｉ５Ｏ１２が好ましい。 The negative electrode active material used for the negative electrode of the lithium secondary battery of the present embodiment is not particularly limited as long as it can insert and desorb metallic lithium or lithium ions. Examples thereof include carbon materials, metal materials, lithium transition metal nitrides, crystalline metal oxides, amorphous metal oxides, silicon compounds, and conductive polymers. The carbon material is not particularly limited, and examples thereof include natural graphite, artificial graphite, non-graphitizable carbon, and graphitizable carbon. Although it does not specifically limit as said metal material, For example, metallic lithium, an alloy, a tin compound etc. are mention | raise | lifted. Specific examples include Li 4 Ti 5 O 12 and NiSi 5 C 6 . Of these, natural graphite, SiO, and Li 4 Ti 5 O 12 are preferable.
　本実施の形態の電極に用いられる導電剤としては、電池性能に悪影響を及ぼさない電子伝導性材料であれば、特に制限なく使用することができる。通常は、アセチレンブラックやケッチンブラック等のカーボンブラックが使用されるが、天然黒鉛（鱗状黒鉛、鱗片状黒鉛、土状黒鉛など）、人造黒鉛、カーボンウイスカー、炭素繊維や金属（銅、ニッケル、アルミニウム、銀、金等）粉末、金属繊維、導電性セラミックス材料等の導電性材料も使用可能である。これらは２種類以上の混合物として使用することもできる。これらのうち、カーボンブラックが好ましい。その添加量は活物質量に対して０．１～３０質量％が好ましく、０．２～２０質量％がより好ましい。 As the conductive agent used for the electrode of the present embodiment, any electronic conductive material that does not adversely affect the battery performance can be used without particular limitation. Usually, carbon black such as acetylene black and kettin black is used, but natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon whisker, carbon fiber and metal (copper, nickel, aluminum) Also, conductive materials such as powder, metal fibers, and conductive ceramic materials can be used. These can also be used as a mixture of two or more. Of these, carbon black is preferred. The addition amount is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass with respect to the amount of active material.
　本実施の形態のリチウム二次電池の電極活物質の集電体としては、構成された電池において悪影響を及ぼさない電子伝導体であれば特に制限なく使用可能である。例えば、正極用集電体としては、アルミニウム、チタン、ステンレス鋼、ニッケル、焼成炭素、導電性高分子、導電性ガラス等の他に、接着性、導電性、耐酸化性向上の目的で、アルミニウムや銅等の表面を、カーボン、ニッケル、チタンや銀等で処理した物を用いることができる。また、負極用集電体としては、銅、ステンレス鋼、ニッケル、アルミニウム、チタン、焼成炭素、導電性高分子、導電性ガラス、Ａｌ－Ｃｄ合金等の他に、接着性、導電性、耐酸化性向上の目的で、銅等の表面をカーボン、ニッケル、チタンや銀等で処理したものを用いることができる。これらの集電体材料は表面を酸化処理することも可能である。また、その形状については、フォイル状の他、フィルム状、シート状、ネット状、パンチ又はエキスパンドされた物、ラス体、多孔質体、発泡体等の成形体も用いられる。厚みは特に限定されないが、１～１００μｍのものが通常用いられる。 As the current collector for the electrode active material of the lithium secondary battery of the present embodiment, any electronic conductor that does not adversely affect the constructed battery can be used without particular limitation. For example, as a positive electrode current collector, aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer, conductive glass, etc., in addition to aluminum for the purpose of improving adhesiveness, conductivity, and oxidation resistance. A material obtained by treating the surface of copper or copper with carbon, nickel, titanium, silver or the like can be used. In addition to the current collector for negative electrode, copper, stainless steel, nickel, aluminum, titanium, calcined carbon, conductive polymer, conductive glass, Al—Cd alloy, etc., adhesiveness, conductivity, oxidation resistance For the purpose of improving the properties, it is possible to use a surface of copper or the like treated with carbon, nickel, titanium, silver or the like. The surface of these current collector materials can be oxidized. Moreover, about the shape, molded bodies, such as a film form, a sheet form, a net form, the punched or expanded thing, a lath body, a porous body, and a foam other than foil shape, are also used. The thickness is not particularly limited, but a thickness of 1 to 100 μm is usually used.
　本実施の形態のリチウム二次電池の電極は、電極活物質、導電剤、電極活物質の集電体、及び電極活物質並びに導電剤を集電体に結着させる結着剤等を混合してスラリー状の電極材料を調製し、集電体となるアルミ箔或いは銅箔等に塗布して分散媒を揮発させることにより製造することができる。 The electrode of the lithium secondary battery of this embodiment is a mixture of an electrode active material, a conductive agent, a current collector of the electrode active material, and a binder that binds the electrode active material and the conductive agent to the current collector. Then, a slurry-like electrode material is prepared and applied to an aluminum foil or a copper foil as a current collector, and the dispersion medium is volatilized to produce the electrode material.
　本実施の形態のリチウム二次電池の電極材料にはスラリー化の粘性調整剤として、水溶性高分子などの増粘剤を使用できる。具体的には、カルボキシメチルセルロース塩、メチルセルロース、エチルセルロース、ヒドロキシメチルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロースなどのセルロース類；ポリアクリル酸、ポリアクリル酸ソーダなどのポリカルボン酸系化合物；ポリビニルピロリドンなどのビニルピロリドン構造を有する化合物；ポリアクリルアマイド、ポリエチレンオキシド、ポリビニルアルコール、アルギン酸ソーダ、キサンタンガム、カラギーナン、グアーガム、カンテン、デンプンなどから選択された１種又は２種以上が使用可能であり、中でもカルボキシメチルセルロース塩が好ましい。 In the electrode material of the lithium secondary battery of this embodiment, a thickener such as a water-soluble polymer can be used as a viscosity modifier for slurrying. Specifically, celluloses such as carboxymethylcellulose salt, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylmethylcellulose; polycarboxylic acid compounds such as polyacrylic acid and polyacrylic acid soda; vinylpyrrolidone such as polyvinylpyrrolidone Compound having structure: One or more selected from polyacrylamide, polyethylene oxide, polyvinyl alcohol, sodium alginate, xanthan gum, carrageenan, guar gum, agar, starch, etc. can be used, among which carboxymethyl cellulose salt is preferred .
　上記電極材料の混合の方法や順序等は特に限定されず、例えば、活物質と導電剤は予め混合して用いることが可能であり、その場合の混合には、乳鉢、ミルミキサー、遊星型ボールミル又はシェイカー型ボールミルなどのボールミル、メカノフュージョン等を用いることができる。 The method and order of mixing the electrode materials are not particularly limited. For example, the active material and the conductive agent can be mixed and used in advance. For mixing in this case, a mortar, a mill mixer, a planetary ball mill can be used. Alternatively, a ball mill such as a shaker type ball mill, a mechano-fusion, or the like can be used.
　本実施の形態のリチウム二次電池は、ポリイミド水分散体を用いたリチウム二次電池の電極用結着剤を用いた電極を使用して構成されるものである。前記リチウム二次電池の電極用結着剤を用いた電極は、正極または負極の少なくとも一方に使用されていればよい。本実施の形態のリチウム二次電池としては特に限定されないが、例えば、正極と負極、この正極と負極との間に設けられ両者を隔離するセパレータと、リチウムイオンを伝導するための溶媒に支持電解質としてリチウム塩を溶解した非水電解液やポリマーまたは高分子ゲル電解質を含む電解質層とで構成される。 The lithium secondary battery of the present embodiment is configured using an electrode using a binder for an electrode of a lithium secondary battery using a polyimide aqueous dispersion. The electrode using the binder for electrodes of the lithium secondary battery may be used for at least one of the positive electrode and the negative electrode. The lithium secondary battery of the present embodiment is not particularly limited. For example, a positive electrode and a negative electrode, a separator provided between the positive electrode and the negative electrode and isolating both, and a supporting electrolyte in a solvent for conducting lithium ions As a non-aqueous electrolyte solution in which a lithium salt is dissolved and an electrolyte layer containing a polymer or a polymer gel electrolyte.
　本実施の形態のリチウム二次電池に使用するセパレータとしては、通常のリチウム二次電池に用いられるセパレータであれば、特に限定されないが、例えば、ポリエチレン、ポリプロピレン、ポリオレフィン、ポリテトラフルオロエチレン等よりなる多孔質樹脂、セラミック、不織布などがあげられる。 The separator used in the lithium secondary battery according to the present embodiment is not particularly limited as long as it is a separator used in a normal lithium secondary battery, and is made of, for example, polyethylene, polypropylene, polyolefin, polytetrafluoroethylene, or the like. Examples thereof include porous resins, ceramics, and nonwoven fabrics.
　本実施の形態のリチウム二次電池に使用する電解液としては、従来からリチウム二次電池に用いられている有機電解液及びイオン液体等を特に制限なく使用することができる。 As the electrolytic solution used in the lithium secondary battery of the present embodiment, an organic electrolytic solution and an ionic liquid that have been conventionally used in lithium secondary batteries can be used without particular limitation.
　本実施の形態のリチウム二次電池に使用する電解液塩としては、特に限定されないが、例えば、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＩ、ＬｉＡｌＣｌ４、ＮａＣｌＯ４、ＮａＢＦ４、ＮａＩ等を挙げることができ、特に、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＡｓＦ６などの無機リチウム塩、ＬｉＮ（ＳＯ２ＣｘＦ２ｘ＋１）（ＳＯ２ＣｙＦ２ｙ＋１）で表される有機リチウム塩を挙げることができる。ここで、ｘ及びｙは、０又は１～４の整数を表し、また、ｘ＋ｙは２～８の整数である。有機リチウム塩としては、具体的には、ＬｉＮ（ＳＯ２Ｆ）２、ＬｉＮ（ＳＯ２ＣＦ３）（ＳＯ２Ｃ２Ｆ５）、ＬｉＮ（ＳＯ２ＣＦ３）（ＳＯ２Ｃ３Ｆ７）、ＬｉＮ（ＳＯ２ＣＦ３）（ＳＯ２Ｃ４Ｆ９）、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）２、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）（ＳＯ２Ｃ３Ｆ７）、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）（ＳＯ２Ｃ４Ｆ９）等が挙げられる。中でも、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（ＳＯ２Ｆ）２、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）２などを電解質に使用すると、電気特性に優れるので好ましい。上記電解質塩は１種単独で用いることもでき、２種以上用いることもできる。このようなリチウム塩は、通常、０．１～２．０モル／リットル、好ましくは０．３～１．５モル／リットルの濃度で、電解液に含まれていることが望ましい。 As an electrolytic solution salts used in the lithium secondary battery of the present embodiment is not particularly limited, for example, LiPF 6, LiBF 4, LiClO 4, LiAsF 6, LiCl, LiBr, LiCF 3 SO 3, LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiI, LiAlCl 4 , NaClO 4 , NaBF 4 , NaI and the like can be mentioned, and in particular, inorganic lithium such as LiPF 6 , LiBF 4 , LiClO 4 and LiAsF 6 salts, and organic lithium salt represented by LiN (SO 2 CxF 2 x +1 ) (SO 2 CyF 2y + 1). Here, x and y represent 0 or an integer of 1 to 4, and x + y is an integer of 2 to 8. Specifically, as the organic lithium salt, LiN (SO 2 F) 2 , LiN (SO 2 CF 3 ) (SO 2 C 2 F 5 ), LiN (SO 2 CF 3 ) (SO 2 C 3 F 7 ) LiN (SO 2 CF 3 ) (SO 2 C 4 F 9 ), LiN (SO 2 C 2 F 5 ) 2 , LiN (SO 2 C 2 F 5 ) (SO 2 C 3 F 7 ), LiN (SO 2 C 2 F 5 ) (SO 2 C 4 F 9 ) and the like. Among them, it is preferable to use LiPF 6 , LiBF 4 , LiN (CF 3 SO 2 ) 2 , LiN (SO 2 F) 2 , LiN (SO 2 C 2 F 5 ) 2 or the like as the electrolyte because it has excellent electrical characteristics. The said electrolyte salt can also be used individually by 1 type, and can also be used 2 or more types. Such a lithium salt is desirably contained in the electrolytic solution at a concentration of usually 0.1 to 2.0 mol / liter, preferably 0.3 to 1.5 mol / liter.
　本実施の形態のリチウム二次電池の電解質塩を溶解させる有機溶媒としては、通常のリチウム二次電池の非水電解液に用いられる有機溶媒であれば特に限定されず、例えば、カーボネート類、ラクトン類、エーテル類、スルホラン類、ジオキソラン類、ケトン類、ニトリル類、ハロゲン化炭化水素類、イオン性液体などがあげられる。前記、カーボネート類としては特に限定されないが、例えば、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネート、エチレンカーボネート、プロピレンカーボネート、エチレングリコールジメチルカーボネート、プロピレングリコールジメチルカーボネート、エチレングリコールジエチルカーボネート、ビニレンカーボネートなどがあげられる。前記、ラクトン類としては特に限定されないが、例えば、γ－ブチロラクトンなどがあげられる。前記、エーテル類としては特に限定されないが、例えば、ジメトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン、テトラヒドロピラン、１，４－ジオキサンなどがあげられる。前記、スルホラン類としては特に限定されないが、例えば、スルホラン、３－メチルスルホランなどがあげられる。前記、ジオキソラン類としては特に限定されないが、例えば、１，３－ジオキソランなどがあげられる。前記、ケトン類としては特に限定されないが、例えば、４－メチル－２－ペンタノンなどがあげられる。前記、ニトリル類としては特に限定されないが、例えば、アセトニトリル、プロピオニトリル、バレロニトリル、ベンゾニトリルなどがあげられる。前記、ハロゲン化炭化水素類としては特に限定されないが、例えば、１，２－ジクロロエタンなどがあげられる。前記、イオン性液体としては特に限定されないが、例えば、メチルフオールメート、ジメチルホルムアミド、ジエチルホルムアミド、ジメチルスルホキシド、イミダゾリウム塩、４級アンモニウム塩などがあげられる。これらの有機溶媒は１種または２種以上を併用して使用することができる。これらの有機溶媒のうち、特に、カーボネート類からなる群より選ばれた非水溶媒を一種類以上含有することが、電解質の溶解性、誘電率及び粘度において優れている点から好ましい。 The organic solvent for dissolving the electrolyte salt of the lithium secondary battery of the present embodiment is not particularly limited as long as it is an organic solvent used for a non-aqueous electrolyte of a normal lithium secondary battery. For example, carbonates, lactones , Ethers, sulfolanes, dioxolanes, ketones, nitriles, halogenated hydrocarbons, ionic liquids and the like. The carbonates are not particularly limited, and examples include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethylene glycol dimethyl carbonate, propylene glycol dimethyl carbonate, ethylene glycol diethyl carbonate, vinylene carbonate, and the like. . The lactone is not particularly limited, and examples thereof include γ-butyrolactone. The ethers are not particularly limited, and examples thereof include dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like. The sulfolanes are not particularly limited, and examples thereof include sulfolane and 3-methylsulfolane. The dioxolanes are not particularly limited, and examples thereof include 1,3-dioxolane. The ketones are not particularly limited, and examples thereof include 4-methyl-2-pentanone. The nitriles are not particularly limited, and examples thereof include acetonitrile, propionitrile, valeronitrile, and benzonitrile. The halogenated hydrocarbons are not particularly limited, and examples thereof include 1,2-dichloroethane. The ionic liquid is not particularly limited, and examples thereof include methyl formate, dimethylformamide, diethylformamide, dimethyl sulfoxide, imidazolium salt, and quaternary ammonium salt. These organic solvents can be used alone or in combination of two or more. Among these organic solvents, it is particularly preferable to contain one or more non-aqueous solvents selected from the group consisting of carbonates from the viewpoint of excellent solubility, dielectric constant, and viscosity of the electrolyte.
　本実施の形態のリチウム二次電池において、ポリマー電解質又は高分子ゲル電解質を用いる場合は、エーテル、エステル、シロキサン、アクリロニトリル、ビニリデンフロライド、ヘキサフルオロプロピレン、アクリレート、メタクリレート、スチレン、酢酸ビニル、塩化ビニル、オキセタンなどの重合体又はその共重合体構造を有する高分子又はその架橋体などの高分子化合物が用いられ、これらは１種単独でも使用でき、２種以上使用することもできる。特に限定されるものではないが、ポリエチレンオキサイドなどのエーテル構造を有する高分子化合物がより好ましい。 In the lithium secondary battery of this embodiment, when a polymer electrolyte or a polymer gel electrolyte is used, ether, ester, siloxane, acrylonitrile, vinylidene fluoride, hexafluoropropylene, acrylate, methacrylate, styrene, vinyl acetate, vinyl chloride A polymer such as oxetane or a polymer having a copolymer structure thereof or a polymer compound such as a cross-linked product thereof is used, and these can be used alone or in combination of two or more. Although not particularly limited, a polymer compound having an ether structure such as polyethylene oxide is more preferable.
　本実施の形態のリチウム二次電池において、液系の電池は電解液を、ゲル系の電池はポリマーを電解液に溶解したプレカーサー溶液を、固体電解質電池は電解質塩を溶解した架橋前のポリマーをそれぞれ電池容器内に収容する。 In the lithium secondary battery of this embodiment, the liquid battery is an electrolyte, the gel battery is a precursor solution in which a polymer is dissolved in the electrolyte, and the solid electrolyte battery is a polymer before crosslinking in which an electrolyte salt is dissolved. Each is housed in a battery container.
　本実施の形態のリチウム二次電池は、円筒型、コイン型、角型、その他任意の形状に形成することができ、電池の基本構成は形状によらず同じであり、目的に応じて設計変更して実施することができる。例えば、円筒型では、負極集電体に負極活物質を塗布してなる負極と、正極集電体に正極活物質を塗布してなる正極とを、セパレータを介して捲回した捲回体を電池缶に収納し、非水電解液を注入し上下に絶縁板を載置した状態で密封して得られる。また、コイン型リチウム二次電池に適用する場合では、円盤状負極、セパレータ、円盤状正極、及びステンレスの板が積層された状態でコイン型電池缶に収納され、非水電解液が注入され、密封される。 The lithium secondary battery of this embodiment can be formed in a cylindrical shape, a coin shape, a square shape, or any other shape, and the basic configuration of the battery is the same regardless of the shape, and the design can be changed according to the purpose Can be implemented. For example, in a cylindrical type, a wound body in which a negative electrode formed by applying a negative electrode active material to a negative electrode current collector and a positive electrode formed by applying a positive electrode active material to a positive electrode current collector are wound through a separator. It is housed in a battery can, sealed with a non-aqueous electrolyte injected, and insulating plates placed on top and bottom. In addition, when applied to a coin-type lithium secondary battery, a disc-shaped negative electrode, a separator, a disc-shaped positive electrode, and a stainless steel plate are stacked and stored in a coin-type battery can, and a non-aqueous electrolyte is injected, Sealed.
　本実施の形態のポリイミド水分散体の製造方法としては、（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応させプレポリマーを合成する工程、プレポリマーを水中で乳化する工程を含む。 As a method for producing the polyimide aqueous dispersion of the present embodiment, (A) acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group are reacted. And a step of emulsifying the prepolymer in water.
　本実施の形態のポリイミド水分散体の製造方法としては、プレポリマー中のアニオン性親水基、カチオン性親水基の中和、又は４級化を行ってから、プレポリマーを水中で乳化する工程を行うことも好ましい。 As a method for producing the polyimide aqueous dispersion of the present embodiment, the step of emulsifying the prepolymer in water after neutralizing or quaternizing the anionic hydrophilic group and the cationic hydrophilic group in the prepolymer is performed. It is also preferable to do this.
　本実施の形態のポリイミド水分散体の製造方法としては、耐電解液性、結着性の観点から、プレポリマーを水中で乳化分散した後、鎖伸長する工程を含むことも好ましい。 The method for producing the polyimide aqueous dispersion of the present embodiment preferably includes a step of chain elongation after emulsifying and dispersing the prepolymer in water from the viewpoint of resistance to electrolytic solution and binding.
　本実施の形態のポリイミド水分散体の製造方法としては、特に限定されないが、必要に応じて溶剤の存在下、プレポリマーを合成する工程、鎖伸長工程を行なうことができる。前記溶剤としては、イソシアネート基と不活性で、かつ、生成するポリイミドを溶解し得る溶剤であれば特に限定されない。これらの溶剤としては、特に限定されないが、例えば、ジメチルアセトアミド、Ｎ－メチル－２－ピロリドンなどがあげられる。反応で使用したこれら親水性有機溶剤は、最終的には除去するのが好ましい。 The method for producing the polyimide aqueous dispersion of the present embodiment is not particularly limited, but if necessary, a step of synthesizing a prepolymer and a chain extension step can be performed in the presence of a solvent. The solvent is not particularly limited as long as it is inactive with an isocyanate group and can dissolve the generated polyimide. These solvents are not particularly limited, and examples thereof include dimethylacetamide and N-methyl-2-pyrrolidone. These hydrophilic organic solvents used in the reaction are preferably finally removed.
　本実施の形態のポリウレタン樹脂（Ｘ）の水分散体を製造の際には架橋剤を使用することもできる。架橋剤としては、特に限定されないが、アジリジン、オキサゾリン、カルボジイミド、変性ポリイソシアネート、ポリエポキシド化合物などがあげられる。これらの架橋剤は１種または２種以上を併用して使用することができる。 In the production of the aqueous dispersion of polyurethane resin (X) of the present embodiment, a crosslinking agent can be used. The crosslinking agent is not particularly limited, and examples thereof include aziridine, oxazoline, carbodiimide, modified polyisocyanate, and polyepoxide compound. These crosslinking agents can be used alone or in combination of two or more.
　本実施の形態のポリイミド水分散体から形成された皮膜の耐電解液性は、実施例に記載の方法において、１０００％以下であることが好ましく、７５０％以下であることがより好ましく、５００％以下であることがさらに好ましい。 In the method described in the examples, the electrolytic solution resistance of the film formed from the polyimide aqueous dispersion of the present embodiment is preferably 1000% or less, more preferably 750% or less, and 500%. More preferably, it is as follows.
　本実施の形態のポリイミド水分散体から形成された皮膜の結着性は、実施例に記載の方法において、０．３０Ｎ／ｃｍ以上であることが好ましく、０．３５Ｎ／ｃｍ以上であることがより好ましく、０．４０Ｎ／ｃｍ以上であることがさらに好ましい。 The binding property of the film formed from the polyimide aqueous dispersion of the present embodiment is preferably 0.30 N / cm or more and preferably 0.35 N / cm or more in the method described in the examples. More preferably, it is more preferably 0.40 N / cm or more.
　［第２の実施の形態に係る実施例］
　以下、実施例及び比較例に基づいて、第２の実施の形態について詳細に説明する。本発明の技術的範囲はこれらの実施例に限定されるものではない。なお、本明細書中に於ける「部」、「％」は、特に明示した場合を除き、「質量部」、「質量％」をそれぞれ表している。 [Example according to the second embodiment]
Hereinafter, based on an Example and a comparative example, 2nd Embodiment is described in detail. The technical scope of the present invention is not limited to these examples. In the present specification, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified.
　＜実施例１＞
　撹拌機、還流冷却管、温度計および窒素吹き込み管を備えた４つ口フラスコにピロメリット酸二無水物（ＰＭＤＡ(ダイセル社製)）１０．２重量部、イソホロンジイソシアネート（ＩＰＤＩ）３１．１重量部、テトラブチルアンモニウムブロミド０．５重量部、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）３８．０重量部と加え、１２０℃で２時間反応させた後、ＤＭＡｃ２３．８重量部、ジメチロールプロピオン酸（ＢｉｓＭＰＡ）６．２重量部と加えて７５℃で２時間反応させた。この溶液にポリブタジエンポリオール（Ｋｒａｓｏｌ　ＬＢＨ－Ｐ２０００）５２．５重量部、メチルエチルケトン（ＭＥＫ）５０．０重量部、トリエチルアミン４．８重量部と加えてさらに７５℃で３時間反応させた後、ＭＥＫ２０．０重量部を加えて希釈し、ウレタンイミドプレポリマー溶液（Ａ）を得た。この溶液の不揮発分に対する遊離のイソシアネート基含有量は１．９１％であった。
　Ａに対し、水１６６．８重量部を加えてホモミキサーを用いて乳化し、続いて、ジエチレントリアミン０．８重量部を加えて鎖伸長反応を３０℃で１時間行った。かかる反応後、ＭＥＫを減圧留去して、水中にポリウレタンイミド樹脂が乳化されてなるポリイミド水分散体（不揮発分：３１．６％、ｐＨ：７．９、粘度：６０１ｍＰａｓ、粒子径：０．０６μｍ）を作製した。 <Example 1>
A four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube is equipped with 10.2 parts by weight of pyromellitic dianhydride (PMDA (manufactured by Daicel)) and 31.1 parts by weight of isophorone diisocyanate (IPDI). Parts, 0.5 parts by weight of tetrabutylammonium bromide and 38.0 parts by weight of N, N-dimethylacetamide (DMAc) and reacted at 120 ° C. for 2 hours, then 23.8 parts by weight of DMAc, dimethylolpropionic acid ( BisMPA) 6.2 parts by weight was added and reacted at 75 ° C. for 2 hours. To this solution was added 52.5 parts by weight of polybutadiene polyol (Krasol LBH-P2000), 50.0 parts by weight of methyl ethyl ketone (MEK), and 4.8 parts by weight of triethylamine, and the mixture was further reacted at 75 ° C. for 3 hours. A part by weight was added for dilution to obtain a urethane imide prepolymer solution (A). The free isocyanate group content with respect to the nonvolatile content of this solution was 1.91%.
To A, 166.8 parts by weight of water was added and emulsified using a homomixer, and then 0.8 part by weight of diethylenetriamine was added to carry out a chain extension reaction at 30 ° C. for 1 hour. After this reaction, MEK was distilled off under reduced pressure, and a polyimide aqueous dispersion obtained by emulsifying polyurethaneimide resin in water (nonvolatile content: 31.6%, pH: 7.9, viscosity: 601 mPas, particle size: 0.00). 06 μm).
　＜実施例２～７、比較例＞
　表３記載の処方に変更した以外は、実施例１と同様の方法により、合成を行った。 <Examples 2 to 7, Comparative Example>
The synthesis was performed in the same manner as in Example 1 except that the formulation shown in Table 3 was changed.
　用いた化合物の略称を以下に示す。
ＰＭＤＡ：無水ピロメリット酸二無水物 (ダイセル製)
ＢＴＤＡ：ベンゾフェノンテトラカルボン酸二無水物 (ダイセル製)
ＢｉｓＭＰＡ：ジメチロールプロピオン酸
ＬＢＨ－Ｐ２０００：Ｋｒａｓｏｌ　ＬＢＨ－Ｐ２０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状ポリブタジエン）
ＬＢＨ－Ｐ３０００：Ｋｒａｓｏｌ　ＬＢＨ－Ｐ３０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状ポリブタジエン）
ＨＢＨ－Ｐ２０００：Ｋｒａｓｏｌ　ＨＬＢＨ－Ｐ２０００（ＣＲＡＹ　ＶＡＬＬＥＹ製、末端水酸基変性液状水素添加ポリブタジエン）
ＰＴＭＧ－２０００：（三菱化学製、ポリテトラメチレンエーテルグリコール）
Ｒ－１５ＨＴ：Ｐｏｌｙｂｄ　Ｒ－１５ＨＴ（出光興産社製、末端水酸基変性液状ポリブタジエン)
ＩＰＤＩ：イソホロンジイソシアネート Abbreviated names of the compounds used are shown below.
PMDA: pyromellitic dianhydride (Daicel)
BTDA: Benzophenone tetracarboxylic dianhydride (Daicel)
BisMPA: dimethylolpropionic acid LBH-P2000: Krasol LBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
LBH-P3000: Krasol LBH-P3000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid polybutadiene)
HBH-P2000: Krasol HLBH-P2000 (manufactured by CRAY VALLEY, terminal hydroxyl group-modified liquid hydrogenated polybutadiene)
PTMG-2000: (Mitsubishi Chemical, polytetramethylene ether glycol)
R-15HT: Polybd R-15HT (manufactured by Idemitsu Kosan Co., Ltd., terminal hydroxyl group-modified liquid polybutadiene)
IPDI: Isophorone diisocyanate
　＜評価方法＞
（耐電解液性）
　ポリイミド水分散体を、４０℃８時間の条件で予備乾燥させた後、８０℃６時間、１２０℃１時間、１５０℃３０分の順で本乾燥させ、２ｃｍ×２ｃｍ、膜厚５００μｍの試験片を得た。
　得られた試験片を、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネート、エチレンカーボネート、プロピレンカーボネートの５種類からなるカーボネート系混合溶媒（重量比で１：１：１：１：１となる組成）に６０℃条件下３日間浸漬後させ、浸漬前後の重量増加率を測定した。
（結着性）
　バインダーとなる樹脂にグラファイト系活物質やＣＭＣを加えたスラリーを、集電体となる銅箔に塗工して作成した電極の剥離強度を測定した。具体的には、負極活物質として、天然黒鉛８１．０ｇ (日本カーボン社製ＡＺＢ－Ａ)およびＳｉＯ９．０ｇ (日下レアメタル社製)、導電剤としてカーボンブラック３．０ｇ（Ｔｉｍｃａｌ社製、Ｓｕｐｅｒ－Ｐ）、増粘剤としてカルボキシメチルセルロース（ＣＭＣ）（第一工業製薬製、品名：セロゲンＷＳ―Ｃ）２重量％水溶液１７５．０ｇ、結着剤として実施例１で合成したポリイミド水分散体 (不揮発分: ３１．６％) １１．１ｇを遊星型ミキサーで混合し、負極スラリーを調製した。この負極スラリーを塗工機で厚み１０μｍの電解銅箔上にコーティングし、１２０℃で乾燥後、ロールプレス処理を行い、負極活物質７ｍｇ／ｃｍ２の負極を得た。上記で作製した電極を１３０℃×８時間減圧乾燥し、プレス後、１８０°ピール剥離強度試験をＪＩＳ　Ｚ０２３７：２００９に基づき実施した。幅１８ｍｍ、長さ３００ｍｍに切断した一般用粘着テープでＳＵＳ３０４鋼板に貼り付けた試験片を、テープの背面が重なるようにテープの端を把持して１８０°に折り返して試験板から２５ｍｍはがした後，試験機に設置した下側の治具にそのテープをはがした部分の試験板の片端を固定し，上側の治具に粘着テープを固定した。試験は５０ｍｍ／ｍｉｎの負荷速度で実施し、測定開始後、最初の２５ｍｍ間の測定値は無視し，２５ｍｍ経過後，試験板から引きはがされたときの引きはがし粘着力の平均値を測定した。 <Evaluation method>
(Electrolytic solution resistance)
The polyimide aqueous dispersion was preliminarily dried at 40 ° C. for 8 hours, and then finally dried in the order of 80 ° C. for 6 hours, 120 ° C. for 1 hour, 150 ° C. for 30 minutes, and a test piece having a thickness of 2 cm × 2 cm and a film thickness of 500 μm. Got.
The obtained test piece was added to a carbonate mixed solvent (composition with a weight ratio of 1: 1: 1: 1: 1) consisting of five kinds of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate. After immersion for 3 days under the condition of ° C., the weight increase rate before and after immersion was measured.
(Binding property)
The peel strength of an electrode prepared by applying a slurry obtained by adding a graphite-based active material or CMC to a resin serving as a binder to a copper foil serving as a current collector was measured. Specifically, 81.0 g of natural graphite (AZB-A manufactured by Nippon Carbon Co., Ltd.) and 9.0 g of SiO (manufactured by Kusaka Rare Metal Co., Ltd.) as the negative electrode active material, and 3.0 g of carbon black (manufactured by Timcal Co., Super) as the conductive agent. -P), carboxymethylcellulose (CMC) (Daiichi Kogyo Seiyaku Co., Ltd., product name: Serogen WS-C) 2 wt% aqueous solution 175.0 g as a thickener, polyimide aqueous dispersion synthesized in Example 1 as a binder ( (Nonvolatile content: 31.6%) 11.1 g was mixed with a planetary mixer to prepare a negative electrode slurry. This negative electrode slurry was coated on an electrolytic copper foil having a thickness of 10 μm by a coating machine, dried at 120 ° C., and then subjected to a roll press treatment, to obtain a negative electrode having a negative electrode active material of 7 mg / cm 2 . The electrode prepared above was dried under reduced pressure at 130 ° C. for 8 hours, and after pressing, a 180 ° peel peel strength test was performed based on JIS Z0237: 2009. A test piece affixed to a SUS304 steel plate with a general-purpose adhesive tape cut to a width of 18 mm and a length of 300 mm was gripped on the end of the tape so that the back surface of the tape overlapped, folded back to 180 °, and peeled off from the test plate by 25 mm Later, one end of the test plate where the tape was peeled off was fixed to the lower jig installed in the testing machine, and the adhesive tape was fixed to the upper jig. The test is carried out at a load speed of 50 mm / min. After starting the measurement, the measurement value for the first 25 mm is ignored, and after 25 mm has elapsed, the average value of the peel-off adhesive strength when the test plate is peeled off is measured. did.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　＜評価結果＞
　実施例１～７から分かるように、本実施の形態のポリイミド水分散体は、得られる皮膜の耐電解液性、結着性が良好であることが分かる。一方、比較例１のように酸価が高い系は、耐電解液性および結着性が劣ることがわかる。 <Evaluation results>
As can be seen from Examples 1 to 7, it can be seen that the polyimide aqueous dispersion of the present embodiment has good electrolytic solution resistance and binding properties of the resulting film. On the other hand, it can be seen that a system having a high acid value as in Comparative Example 1 is inferior in electrolytic solution resistance and binding property.

Claims (12)

  1. （Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応して得られるポリイミド水分散体。 A polyimide aqueous dispersion obtained by reacting (A) an acid anhydride, (B) polyisocyanate, and (C) a compound having one or more active hydrogen groups and a hydrophilic group.
  2. 　ポリイミドの酸価が、２０～１００ｍｇＫＯＨ／ｇである、請求項１記載のポリイミド水分散体。 The polyimide aqueous dispersion according to claim 1, wherein the acid value of the polyimide is 20 to 100 mgKOH / g.
  3. 　請求項１または２記載のポリイミド水分散体を鎖伸長して得られるポリイミド水分散体。 A polyimide aqueous dispersion obtained by chain-extending the polyimide aqueous dispersion according to claim 1 or 2.
  4. 　酸価が５０ｍｇＫＯＨ／ｇ以下である、請求項１記載のポリイミド水分散体。 The polyimide aqueous dispersion according to claim 1, wherein the acid value is 50 mgKOH / g or less.
  5. 　（Ｅ）アミンを用いて鎖伸長して得られる請求項４記載のポリイミド水分散体。 (E) The polyimide aqueous dispersion according to claim 4, obtained by chain extension using an amine.
  6. 　請求項４または５記載のポリイミド水分散体を用いたリチウム二次電池の電極用結着剤。 A binder for an electrode of a lithium secondary battery using the polyimide aqueous dispersion according to claim 4 or 5.
  7. 　請求項６記載のリチウム二次電池の電極用結着剤を用いた電極。 An electrode using the binder for an electrode of a lithium secondary battery according to claim 6.
  8. 　請求項７記載の電極を有するリチウム二次電池。 A lithium secondary battery having the electrode according to claim 7.
  9. 　（Ａ）酸無水物、（Ｂ）ポリイソシアネート、および（Ｃ）１個以上の活性水素基と親水基を有する化合物を反応させプレポリマーを合成する工程と、
    　プレポリマーを水中で乳化する工程と、を含むポリイミド水分散体の製造方法。     (A) acid anhydride, (B) polyisocyanate, and (C) a step of reacting a compound having one or more active hydrogen groups and a hydrophilic group to synthesize a prepolymer;
    Emulsifying the prepolymer in water, and a method for producing a polyimide aqueous dispersion.
  10. 　さらに鎖伸長する工程を含む請求項９記載のポリイミド水分散体の製造方法。 The method for producing a polyimide aqueous dispersion according to claim 9, further comprising a step of chain extension.
  11. 　酸価が２０～１００ｍｇＫＯＨ／ｇである、請求項９または１０記載のポリイミド水分散体の製造方法。 The method for producing a polyimide aqueous dispersion according to claim 9 or 10, wherein the acid value is 20 to 100 mgKOH / g.
  12. 　酸価が５０ｍｇＫＯＨ／ｇ以下である、請求項９または１０記載のポリイミド水分散体の製造方法。 The manufacturing method of the polyimide water dispersion of Claim 9 or 10 whose acid value is 50 mgKOH / g or less.
PCT/JP2017/003346 2016-04-14 2017-01-31 Aqueous polyimide dispersion, binder for electrodes, electrode, secondary battery and method for producing aqueous polyimide dispersion WO2017179268A1 (en)

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JP2000103849A (en) * 1998-09-25 2000-04-11 Dainippon Printing Co Ltd Polyimide for electrodeposition
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JP2011094037A (en) * 2009-10-30 2011-05-12 Toyo Ink Mfg Co Ltd Flame-retardant adhesive composition, flame-retardant adhesive sheet, and flexible printed wiring board
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